SEA LILIES, STARFISHES, ETC.—CLARK. 109 
«describe. Perhaps it may be most easily stated thus: in C. 
floridanus and C. longicollis, the genital plates are about the 
same width as the bare interambulacral space, while in C. 
australis they are about the same width as the entire inter- 
ambulacrum. In C. australis, the outer half of the upper 
interambulacral plates, which lack a primary tubercle, is well 
covered by a couple of secondary and 10-20 miliary tubercles ; 
in C. longicollis there are very few such tubercles on those 
plates ; in C. floridanus, the tubercles are numerous, but are 
very small, so the surface of the outer end of the plate is 
granular, rather than tuberculous. The Australian species 
resembles C. longicollis in the large size of the dorsal ambu- 
lacral tubercles ; they are even larger than in that species. 
It is also like C. longicollis in the characters of fully developed 
primary spines, but the collar is lower and the colouration is 
totally different. Coelopleurus has been taken at the Kei 
Islands and at New Britain, but its occurrence in Bass Strait 
extends the range of the genus over two thousand miles at 
least. 
Loc.—Kastern Slope, Bass Strait, 60-112 fathoms. 
Family ECHINIDA. 
Genus Ecuinus, Linné. 
ECHINUS HoRRIDUS, A. Agassiz. 
(Plate xxxix.; Plate xl., fig. 1-2.) 
Echinus horridus, A. Agassiz, Proc. Amer. Acad., xiv., 1879, 
p- 203. 
The specimen from south of Gabo Island, Victoria, is not 
only the most remarkable Echinoid in the collection, but is one 
of the most extraordinary Sea-urchins which has ever been 
taken. It has a horizontal diameter at ambitus of 80 mm. 
and a vertical height of 115 mm. ; there are 33 or 34 coronal 
plates and 61-62 ambulacrals, in each column ; the abactinal 
system is 12 mm. across (.15 h.d.) and all the ocular plates 
plates are exsert; the anal system is nearly 5 mm. across, 
and is covered by about 160 small plates, many quite granule- 
like, among which the flat, circular suranalis very prominent ; 
the spines are nearly all missing; those which remain are 
small secondaries or the bases of broken, bright red primaries ; 
the actinostome is very small, only 11 mm. across, or less than 
.15 h.d. I have compared this specimen with the fragments 
of a slightly larger specimen of HL. horridus from off southern 
