GENEEA AND GROUPS OF THE ECHINOIDEA. 243 



Fossil. Crag : England. Eocene, Miocene, Pliocene : Europe. 

 Miocene : Asia (Sind and Madura). Tertiary : N. America, 

 West Indies. 



Becent. Arctic Seas, N. Atlantic to Azores, Mediterranean, 

 West Indies and Brazil, Pacific, W. coast of America. 7-450 fms. 



This definition covers the recent forms and most of the Ter- 

 tiary species, but Wriglit's B. tuberculatus has necessitated the 

 addition regarding the occasional presence of larger tubercles 

 within the peripetalous fasciole, as in Metalia. 



The genus JBrlssomorpha, Laube, 1871, is similar to Brissus ; 

 and the genus Heterohrissus, Manzoni and Mazzetti, 1877, is 

 unsatisfactory on account of the indifferent state of preservation 

 of the specimens of the sole species ; it may be a Brissus. 



Brissus depressus, a form which has never been obtained in a 

 condition of preservation worthy of description, has been made 

 the type of a new genus, Leiopneustes, by M. Cotteau, 1885, Pal. 

 Erang., Terr. Cret. p. 123. Considering that it is written 

 "fascioles absent or very slightly apparent," the value of the 

 genus is problematical. 



Subgenus Meoma, Gray, 1851 (genus), Ann. Sf Mag. Nat. Sist. 

 vol. vii. p. 132; 1855, Gat. Bee. Ech. Brit. Mus. pt. i. p. 56. 

 Luthen, 1863 (pub. 1864), Vid. Medd.f. Nat. For. i Xjoh. 

 p. 120. A. Agassiz, Bevision, 1872-74 (subgenus), pp. 358, 

 603. Love'n, 1874, Btudes, pi. 35. 

 Test moderately stout, cordif orm, the paired ambulacra sunken 

 in deep grooves, antero-lateral divergent. 



Peripetalous fasciole slender, flexuous, entering the interradia 

 between the petals. A subanal fasciole slender and incomplete 

 above, a slender offshoot passing abactinally on either side of the 

 periproct. 



Fossil. Tertiary : Cuba. Miocene : W. Sind. The genus is not 

 represented in the Australian Tertiaries. 



Becent. Gulf of California, Acapulco, West-Indian Islands, 

 Gulf of Elorida. 242 fms. 



G-enus Spatangomokpha, Bohm, 1882, DenJcscJi. d. Tcais. Ahad. 

 Wiss. Wien, Bd. xlv. p. 367. 

 Test moderate, elongate oval, depressed, notched anteriorly, 

 highest and truncated posteriorly, depending below the periproct. 



16* 



