SEA LIX,[ES, STAKFISHES, ETC. — CLAEK. 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 mihary 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 Austrahan 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. 



-Lac. — Eastern Slope, Bass Strait, 60-112 fathoms. 



Family ECHINIDiE. 



Genus Echinus, Linne. 



Echinus horridus, A. Agassiz. 



(Plate xxxix. ; Plate xl., fig. 1-2.) 



Echinus horridus, A. Agassiz, Proo. 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 suranal is 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 E. horridus from off southern 



