6 Ech. 
ECHINODERMATA. 
The stellate condition of the centre- dorsal in that genus appears to be 
one of the “ concluding stages of a long series of changes in the shape 
and ’relations of the centro-dorsal, which do not commence until some 
time after the loss of the stem.” 
With regard to the so-called “ventral nerve,” the author is able to 
show that out of 51 Actinometrce, 28 have grooveless arms ; sections show 
the absence of the “ ventral nerve.” In some examples, one of the 
posterior arnbulacral grooves does not extend beyond the disc, and the 
two arms to which it should have gone receive no branches from any of 
the adjacent grooves ; in a gigantic Philippine species, many of its 
hundred arms are “ nerveless.” These facts have a very important bear- 
ing on the nervous character of the “ sub-epithelial bands.” 
R. S. Rergh, in Bidrag til Opfattolsen af Kl^vniug og Kimbladdanelse 
hos Echiniderme (Vid. Modd. 1879, pp. 255-201), gives a wood-cut of 
the gastrula-stage of Pdammechinus miliar is. 
Genera and Species. 
ECHINOIDEA. 
The following are the names of the new species or genera described 
by Agassiz (1) I — 
Dorocidaris bracteata (closely allied to D. pajpillata). 
Porocidaris elegans. 
Goniocidaris Jlorigera. 
Salenia hastigera. 
Podocidaris prionigerct. 
Aspidodiadema (g. n.)j intermediate between the Cidaridee proper and 
the DiadematidcG, for A. tonsum and micro-tuberculatum. 
Micropyga (g. u., allied to Astropygd) tuberculata. 
xlsthenosoma pellucida grubiiy coriacea l-eum'], and tessel- 
lata 
Phormosoma luculenta\j- 111171 } and tenuis[;ue]. 
Prionechinus (g. n.) sagiuiger. 
Cottaldia forbesiana. 
Trigonocidaris monolini. 
Echinus horridus. 
Catopygus rccens. 
Palicotropus loveni. 
Pourtalesia hisjnda, laguncida, carinala, ceralopyga^ and rosed. 
Cionobrissus (g. n. ; somewhat like Brissopsis) revinctus. 
Echinocrepis (g. u.) cuneata. 
Spatagocystis (g. n.) ; like some of the following new genera, this hiiS 
decided allinitics to the Pourtalcsicc, and some similarity to Jfolaster, 
Cardiasler, and Ananchytes ; for S. challengeri. 
Urechinus (g. n.) naresianus. 
CgsUchinus (g. n.), with the general appearance of Ananchytes^ for Ci 
loyvillii, clypeatus^ and vesica. 
Ilomolampas falva. 
