Report on the zoological collections made in the Indo-Pacific Ocean ...

—ALCTONARIA, 331Tcuconomii.—The results of the collection in this respect are notless interesting than are those of the distrihution. In the case of onefamily (the Melitha3id;), a structural character has for the first timecome to light, which illustrates the existence of a similar characterin other families of this natural but very manifold Order : I refer tothe occurrence of two kinds of zooids. In one case (in the samefamily) it has been found desirable to establish a new genus, and thenumber of new species is relatively large. The Melithteidte show aremarkable development here. A remarkable member of the usuallyrare family Briareida3 has been assigned by me to the genus Icili-(jorgia, hitherto known only from the West Indies. The number ofspecies of this family found here is relatively large, and includessome rare and very strange forms {Solenocdulum, Leucoella). Twopoints of general importance for the family Gorgoniidae may be consideredto have been decided by a study of the series which representsthe new species, Lepto(jorgia australiensis, in this collection1. That colour alone cannot be taken as a character of specific importance.2. That characters derived from the shape, depth, partialpresence or absence of superficial grooves in the cortex, or theirpartial rej^lacement by raised lines, as seen in dry specimens, arenot of specific, much less of family value, as held by Dr. Gray forsome Gorgoniidae (see Catalogue Lithoph, Brit. Mus., p. 24, Elliselladce).Measurements and Terms employed.—The measurements of spiculesare those of average greatest specimens of each form of spicule. Ihave adopted Yerrill's term verruca to signify that specialized partof the cortex which contains the retracted zooid. When describingthem I have applied the term longitudinal to the radiating spiculesof the verruca, and liorizontal to those which are circularly arrangedwith regard to its centre.Classification.—I have followed in the main the arrangementadopted by Kolliker in his Icones 'Histiologicae.'ALCYO:^IIDJE.Alctoniin^.The absence of both Sarcophytum and Alcyonium from the collectionis perhaps due to the absence of in-shore reefs in the areaexamined. An Alcyonium was described from Port King George inSouthern Australia by Q,uoy and Gaimard from the ' Astrolabe 'voyage ; but Lamarck's A. 2^'"'tridosu7n, from that locality, I haveascertained to be a siliceous Sponge.