/ 



132 Mr. J. E. Gray on new genera and species of Spatangidse, 



This genus differs from Brissus in the incompleteness of the 

 subanal fasciole^ the indistinctness of the subanal disk, and in 

 the entire absence of the anterior ambulacral pores. It differs 

 from Faorina in wanting the lateral fascicle. Dorsal tubercles 

 small, equal. 



c/ (Zq,cu^^^t/t^ Meoma grandis. Subcordate, rather convex. 

 UOa,. Hab. Australia, Capt. Sir Edward Belcher, K.C.B., R.N. 

 ^,^c/'>" 



/ .3sx} , Faorina. Shell ovate, subcordate, ventricose; vertex central, 



hinder end truncated, without any distinct subanal disk ; am- 

 bulacra sunken, the lateral ones regularly diverging, anterior 

 longest, anterior odd one obliterated, marked by a deep groove, 

 all surrounded by a rather sinuous peripetalous fasciole without 

 any lateral or subanal fasciole or anal plate ; ovarial pores two, 

 three or four. 



Faorina chinensis. Purple, with a smooth band between the 

 upper anterior tesserse, and a smooth vertical band over the su- 

 ture from the end of the anterior lateral ambulacra to the front 

 of the mouth. 



Hab. China, J. R. Reeve, Esq. 



Faorina antarctica. Subcordate, rather depressed ; lateral am- 

 bulacra ovate, longitudinal, very deep, forming a very distinct 

 rib on the inner side of the shell ; peripetalous fasciole broad, 

 sinuous. 



Hab. South Polar Seas, Capt. Sir James Ross's expedition. 



This species differs from Faorina cavernosa (Erichson, Arch. 

 1845, t. 11. f. 2) in the ambulacra being less broad, and in the 

 fasciole being much broader and more distinct. 



Tripylus Philippii. Cordate, rather depressed; lateral ambu- 

 lacra oblong, linear, the hinder pair not half the length of the 

 anterior one, the sides of the hinder part of the peripetalous 

 fasciole parallel. 



Hab. . 



The genus Tripylus of Philippi differs from Desoria and Schi- 

 zaster in the regular cordate form and central vertex, and differs 

 from Brissiopsis, with which M. Agassiz confounded it, in the 

 absence of the subanal fasciole. 



Desoria. Shell ovate, convex, vertex subanterior ; ambu- 

 lacra narrow, sunken, like Brissus, the anterior odd one formed 

 of a series of small double pores, all surrounded by a very sinuous 

 peripetalous fasciole giving off a lateral fasciole, which extends to 

 the vent without any distinct subanal fasciole or subanal disk. 



Very like Brissus, but dstinguished by the presence of the 

 lateral fasciole and the absence of the subanal one and disk. 



