430 Mr. Gray on the Sea BggL fDEtrl 



bulacraten, in pairs, radiating without interruption from the vertex 

 to the mouth ; mouth subcentral ; anus dorsal. 



E, Bryerii, n. Nucleolites scutata. Lam, Bryerius, t. 6, 

 f.1,2. 



Fam.5. SPATANGIDiE. 



Body ovate or heart-shaped, rather gibbous, covered with 

 numerous small, and some scattered, rather larger tubercles ; 

 spines setaceous, depressed, unequal-sized, the larger tubercles 

 perforated ; ambulacra subcomplete, interrupted at the edge, 

 forming a cross, uniting by pairs, each formed of two rows of 

 perforations ; mouth submarginal, below, transverse, destitute of 

 jaws ; internal cavity destitute of vertical pillars ; ovarial pores 

 four, close together, vertical ; interovarial pores very small ; 

 corpus spongiosum vertical, anterior. 



The crustaceous covering of the body of these animals is thin, 

 and formed of twenty bands of pieces, like all the other Echinida, 

 but the interambulacral areae are unequal ; the posterior lateral ones 

 are usually very broad, the lengthening of which is formed more 

 especially by the extension of the pieces of the posterior band 

 of this area; the hinder middle area is rather irregular ; the pos- 

 terior series of each of the two hinder ambulacra being extended 

 into it just below the anus so as to form an isolated subpentan- 

 gular piece, externally marked by a smooth groove, the ambu- 

 lacra tnen being extended beyond it, leaving a central ovate, or 

 lanceolate medial inferior area. Round the mouth there are five 

 grooves, the continuation of the ambulacra, which are more or 

 less perforated with holes, through which pass out branched ten- 

 tacula, like those of Holothuria, see Leske, t. 43, f. 5. 



The species like Brusus purpureus, which have very distinct 

 larger spines, are aUied to Cidarldm by the tubercles of the lar- 

 ger spines being perforated. The whole family is allied to 

 HolothuriadcB by the thin texture of the crustaceous covering, 

 and by the mouth being destitute of jaws, and surrounded by 

 branched appendages. 



*Echino spatangus, Bryerius, Cor marinum, Klein, 

 Spatangus, Klein. 



Body cordiform ; back with large perforated tubercles ; am- 

 bulacra four, the posterior one wanting, or not perforated. 

 S. purpureus, heske, t. 43, f. 3, 5 ; t. 45, f. 5. 



EcMiNocARDiUM, Vau PkeL? 



Body cordiform ; back equal, tuberculated ; ambulacra five, 

 the posterior one in a groove, perforated. 



E. atropos. Spatangus, Lam. E. pusillus, Leske, t. 38, f. 5 ; 

 Klein, t. 24, Lode. E. seba, Seba, iii. t. 10, f. 21, A B. 

 **Echino brissus, Bryerius, Ovum marinum, Klein, 



