bo 
ORDER V EUECHINOIDEA—SPATANGOIDEA 247 
postero-lateral shorter than the others, with elongate, conjugated pores. 
Periproct supra-marginal ; apical system eccentric in front. : 
Broad subanal fasciole. Abundant in Middle and Upper a poy 
Cretaceous ; less common in Eocene and Miocene. 7 
Brissus, Klein (Brissomorpha, Laube); Meoma, Gray ; 
Metalia, Gray. ‘Tertiary and Recent. Lthinobrissus, A. Ag. 
Recent. 
Brissopsis, Ag. (Deakia, Pavay), (Fig. 402). Amb 
unequal, bare and large near the peristome. Anterior 
Amb slightly sunken, with small pairs of close pores. Rana. 
Paired Amb sunken, the antero-lateral pair sub-petaloid, — sicraster coranganium, 
equal to or larger than the postero-lateral, straight or 1#™- Apical system. 
curved. A subanal and peripetalous fasciole. Tertiary and Recent. 

Sub-genus Cyclaster, Cotteau. Antero-lateral Amb divergent. Eocene. 
Brissopatagus, Cotteau. Allied to Brissopsis. Eocene. 
Spatangus, Klein. Anterior Amb in a broad, deep groove, with distant 

Micraster cortestudinariuwm, Goldf. White Chalk ; Meudon, near Paris. Natural size. 
pairs of small pores. Paired Amb petaloid, with broad, sunken poriferous 
zones. Periproct large, supra-marginal, transverse. dmb 
with large crenulate and perforate primary tubercles, and 
fine granulation. JSubanal fasciole only. Tertiary and 
Recent. 
Maretia, Gray. Tertiary and Recent. 
Hupatagus, Ag. Anterior Amb in a shallow, abactinal 
depression, narrow, and with small, distant pairs of pores. 
The paired Amb petaloid dorsally, long, wide, closed ; por- 
iferous zones broad, more or less sunken ; pores dissimilar. 
Peripetalous and subanal fasciole. Tertiary and recent. 
Sub-genus Macropneustes, Ag. (Peripneustes, Cott.), (Fig. 402 bis). 
Test large, thick, cordiform. Petals elongate or broad, grooved or 
semi-flush, open or imperfectly closed. Poriferous zones of equal width with the inter- 
poriferous. Eocene and Recent. 
Gualtieria, Desor. Eocene. Echinocardium, Gray ; Breynia, Desor ; Lovenia, 
Ag. and Desor. Tertiary and Recent. 

Fia. 402. 
Brissopsis lyrifera, 
Forbes. Apical system, 
enlarged (after Loven). 
