A monograph of the British fossil corals - kreidefossilien.de

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X BRITISH FOSSIL CORALS. duced by their existence must he considered as one of the most striking features of this zoological division. The septa are developed successively, as the Polyp grows, and in general six of these vertical laminae constitute the primary or fundamental cyclum. Shortly afterwards a second circle, equally composed of six septa, appears, and the twelve locuh situated between these secondary septa and the primary ones are next subdivided by a third row or cyclum of twelve younger septa. The number of the septa often augments still more, and is sometimes carried very high ; but in general the primary septa continue to be more developed than the others, and thus divide the whole of the radiate structure into six distinct groups or systems. In some instances, however, the secondary, or even the tertiary, septa grow so rapidly, that they soon exactly resemble those of the first cyclum, and in such cases the number of the systems is appai'cntly much greater.^ Sometimes the number of the primary septa is, on the contrary, reduced to four, or perhaps even to two, but never reaches eight, as would be the case if the Polypi of this order had ever eight tentacula and eight perigastric lamellae, a sti-ucture which is always met with in the order of Alcyonaria. It is also to be noted, that the septa vary considerably in their structure, and thus furnish most important characters, not only for the distinction of species and genera, but even for the formation of higher zoological divisions in this order of Polypi. Zoantharia may be divided into two principal groups, characterised by the structure of the parietes of their body. One of these sections comprises the species in which the dermal tissue remains soft and flexible ; the other contains those the teguments of which assume an osseous structure and constitute a calcareous Polypidom. The ScLERENCHYMATOUS ZoANTHARiA are the only Zoophytes of this order which we shall have to mention in the sequel of this work ; it would, therefore, be superfluous for us to treat of the classification of Malacodermous Zoantharia ; but it is necessary that we should give a detailed accovxnt of the methodical arrangement of the first of these groups. Little is known concerning the anatomical modifications of the soft parts in the difierent representatives of this zoological form ; but the structm-e of the Polypidom ofiers great variety, and furnishes, to an attentive observer, data which appear sufficient for the natmal classification of Sclerenchymatous Zoantharia. The principal characters which we have made use of for that pm-pose, are derived from the dense or porous structure of the sclerenchyma ; the predominance of the septal apparatus, the miu-al tissue or the tabular system in the formation of the corallum ; the existence or the absence of dissepiments uniting the septa and subdividing the loculi, and the mode of development of the Polj^^i. Five principal divisions may be thus established in this section, and may be designated by the following appellations : Zoantharia aporosa, Zoantharia perforata, Zoantharia tabulata, Zoantharia riir/osa, and Zoantharia caulicidata. 1 The laws by which the development of the septal apparatus appears to be regulated, have been laid down in our memoir on the Structure of Corals, 'published in the Annales des Sciences Naturelles, 3°" sene, torn, ix, 1848.
; INTRODUCTION. xi Sub-order 1. ZOANTHARIA APOROSA. Corallnm composed essentially of lamellar dermic sclerenchyma, with the septal apparatus highly developed, completely lamellar, and primitively composed of six elements ; no tabidte. The fohaceous or lamellar structm-e of the calcified tissue, which furnishes one of the principal characters of these Corals, is always recognisable in the exterior part of the septa : these organs are never composed of ii-regular trabiculse, as is the case in Porites, or even perforated, excepting near their inner margin. The walls are also very seldom porous, and usually constitute an uninterrupted theca, so as to admit of no communication between the visceral chamber and the exterior, except by the cahce. The septa form the most important part of the Polypidom ; they augment more or less in number as the Polyp rises, but in general remain unequally developed, and are disposed in groups corresponding to the six primitive radii, or to a multijile of that number, but never present a quaternary arrangement, as is often the case in Cyathophylhda^ The visceral chamber remains open from top to bottom, or is only subdivided by synapticidse, or by irregular dissepiments, which extend from one septum to another without joining together, so as to form a series of chstinct tabulaj or discoid floors ; a mode of structure which is on the contrary prevalent, and very remarkable in most of the Corals belonging to our third and fourth sections. The Zoantharia aporosa are the most lamelliferous and steUiform of aU the Corallaria they are very numerous, and belong to four principal families : the Turbinolidce, the Oculinidce, the Astreida, and the Funf/idm ; but some few of them cannot find a proper place in any of these natiu:al divisions, and appear to constitute a certain number of satellite or transitional minor groups, which partake of some of the characters of two or more of the above-mentioned principal forms, without possessing any structural peculiarity of sufficient importance to make us consider them as the representatives of a special type; these groups are therefore not of the same zoological value as the preceding, and in order to point out then' aberrant nature, we shall designate them by names indicative at once of then* principal affinities and their dependent character : Pseudastreidte and PmndoturbinoUda for example. Family I. TURBINOLID^. Milne Edwards and Jules Haimc, Becherches sur les Polypiers ; Annates des Sciences NatureUes, 3"' serie, torn, ix, p. 211, 1848.; CoraUum in general simple, never fissiparous, and multiplying by lateral gemmation in compound species. Interseptal loculi extending from the top to the bottom of the visceral
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Page 8 and 9: i. E. ADLJIED, PBINTr.B, BARTHOLOME
Page 10: e 7b-^,pi'? PRINTED BY C. AND .1. A
Page 13 and 14: INTRODUCTION. iii centre of the ram
Page 15 and 16: INTRODUCTION. v certain parts of th
Page 17 and 18: INTRODUCTION. vii in which the mult
Page 19: INTRODUCTION. ix Sub-class 1. CORAL
Page 23 and 24: INTRODUCTION. xiii 3. Genus Acantho
Page 25 and 26: ; INTRODUCTION. xv formed by proces
Page 27 and 28: ; INTRODUCTION. xvii IS. Genus Plat
Page 29 and 30: INTRODUCTION. xix Aberrant Group. P
Page 31 and 32: INTRODUCTION. xxi 8. Genus Amphelia
Page 33 and 34: INTRODUCTION. xxiii 3. Genus Dkndra
Page 35 and 36: INTRODUCTION. xxv 5. Genus Ccelosmi
Page 37 and 38: INTRODUCTION. xxvii in the two prec
Page 39 and 40: ; INTRODUCTION. xxix 23. Genus Pler
Page 41 and 42: ; INTRODUCTION. xxxi 30. Genus Hete
Page 43 and 44: INTRODUCTION. xxxiii 30. Genm Symph
Page 45 and 46: ;; INTRODUCTION. xxxv 44. Gentts Tr
Page 47 and 48: LNTRODUCTION. xxxvii 50. Genus Dipl
Page 49 and 50: INTRODUCTION. xxxix Section IV.—
Page 51 and 52: ; INTRODUCTION. xli 64. Genus Astro
Page 53 and 54: INTRODUCTION. xliii which thus form
Page 55 and 56: ; INTRODUCTION. xlv 79. Genus Oclan
Page 57 and 58: INTRODUCTION. xlvii 4. Genus Micbab
Page 59 and 60: INTRODUCTION. xlix 14. Genus Ctclos
Page 61 and 62: INTRODUCTION. li the sclerenchyma,
Page 63 and 64: INTRODUCTION. liii 7. Genus Stephan
Page 65 and 66: INTRODUCTION. Iv Family VII. PORITI
Page 67 and 68: . INTRODUCTION. Ivii Second Tribe
Page 69 and 70: INTRODUCTION. lix 4. Genus Fistulip
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INTRODUCTION. hi but much shorter,
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INTRODUCTION. Ixiii Family X. SERIA
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; INTRODUCTION. Ixv Family XIII. CY
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INTRODUCTION. kvii 7. Gejius Hallia
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INTRODUCTION. hix 17. Genus Gonioph
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INTRODUCTION. Ixxi or costal radii
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INTRODUCTION. • Ixxiii The genera
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INTRODUCTION. Ixxv Family I. ALCYON
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INTRODUCTION. Ixxvii Second Tribe
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INTRODUCTION. Ixxix 1 7. Ge?ius Dis
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INTRODUCTION. Ixxxi 8. Genus Soland
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INTRODUCTION. Ixxxiii 3. Ge7lUS ViR
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INTRODUCTION. Ixxxv Order 3. PODACT
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CORALS OF THE UPPER CHALK. 46 towar
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CORALS OF THE UPPER CHALK. 47 Famil
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: CORALS FROIM THE UPPER CHALK. 49
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CORALS FROM THE UPPER CHALK. 51 Tho
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CORALS FROM THE LOWER CHALK. 53 CHA
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CORALS FROM THE LOWER CHALK. 55 the
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CORALS FROM THE UPPER GREENSAND. 57
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; CORALS FROM THE UPPER GREENSAND.
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CORALS FROM THE GAULT. CHAPTER VI.
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; CORALS FROM THE GAULT. 03 3. Genu
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CORALS FROM THE GAULT. 65 found nea
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CX)RALS FROM THE GAULT. G7 and have
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' Petref. : ; CORALS FROM THE GAULT
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; CORALS FROM THE LOWER GREENSAND.
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TAB. IX. CORALS FROM THE UPPER CHAL
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TAB. XI. CORALS FROM THE GAULT. Cya
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302 TABLE OF BRITISH FOSSIL CORALS.
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304 TABLE OF BRITISH FOSSIL CORALS.
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A. GENERAL INDEX;
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308 GENERAL INDEX.
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310 GENERAL INDEX.
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312 GENERAL INDEX. Dendrophyllia de
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314 GENERAL INDEX. . Halysites cate
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310 GENERAL INDEX.
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318 GENERAL INDEX.
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320 GENERAL INDEX.
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322 GENERAL INDEX. Xenia Zaphrentis
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