"^'iSi!^,i:t" ^MMm in the Uni.

486 ECHINODERMATA.
D.—Ambulacral areas broad. Pedicellariae of four different forms—gemmiform,
tridactyle, ophiocephalous or buccal, and trifoliate (the last form
absent perhaps in some genera)—and never directly fixed to the stem.
Spicules of the ambulacral tubes arcuate, with the extremities curved downwards,
simple or surmounted with a hook at each of the lateral curvatures.
1. Pores disposed in transverse ranges of three pairs.
a. Impressions around the ambulacral and interambulacral plates;
pores at the angles of these plates. Tubercles sometimes crenulated,
never perforated :—" Salmaciens."
Genera: Temnopleurus, Salmacis, Microcyphus, Mespilia.
/3. Neither impressions nor pores at the circumference of the plates.
Tubercles neither crenulated or perforated:—" Echiniens."
Genera: Amblypneustes, Echinus, Sphcerechinus, Psammechinus, Boletia.
2. Pores disposed in more or less curved ranges containing 5 or 6 pairs:—
" Loxechiniens."
Genera: Toxopneustes, Loxechinus.
3. Pores forming in each ambulacral demiarea two regular lateral
bands, between which are found, sometimes an irregular median
line, sometimes an unlimited number of sporadic pores:—" Tripneustiens."
Genera: Tripneustes, Holopneustes.
E.—General characters of group D; but the spicules of the ambulacral
tubes have the form of perforated plates :—" Heliocidariens."
Genus Heliocidaris.
II—Test elliptical. Pedicellariae of the tridactyle, ophiocephalous, and
gemmiform types, the latter having the jaws terminated by unsymmetrical
hooks. Pores disposed in ranges of four pairs at least, this number of
pairs increasing towards the summit of the test. Spicules of the ambulacral
tubes simple, arcuate, recurved downwards at their extremities:—
" EchinomStriens."
Genera : Echinometra, Aerocladia, Podophora.
Verrill (Am. J. Sc. vol. xlix. p. 101) maintains the validity of his generic
name Euryechinus for E. drobachiensis and E. lividus, the name Toxopneustes
having been originally applied by Agassiz in 1841 to urchins of a different
generic type. Toxocidaris, A. Agassiz, 1862, he considers also synonymous
with Toxopneustes, Agass. 1841.
Carpenter, Jeffreys, and W. Thomson mention (P. R. Soc. Nov. 18, 1869,
p. 450) an Echinid allied to Astropyga, but with a flexible test, taken N. W.
of the Hebrides. The same naturalists found it again off the coast of Spain
(U>. Dec. 8, 1870, p. 154).
Clypeaster speciosus, sp. n., Verrill (I. c. p. 95), La Paz.
Encope californica, sp. n., Verrill (I. c. p. 97), La Paz.
IIOLOTHUROIDEA.
8ynapta fasciata, sp. n., Kuhl et Van Hasselt, Bijd. tot de Dierk. 1869,
p. 2, West coast of Java.
Holothuria maeulata, sp. n., Kuhl et Van Hasselt (/. c. p. 2), west coast
of Java. "