14(3 



lacra, brusi t and those which have five, spatangi ; the ge- 

 neral form and characters of both of which are represented 

 in PL ii. fig. 13, 11. 



Brissus, (Ovum-marinum), PL ii. fig. 13 ; Spatangus, 

 (Cor. marinumj, fig. 11. 



* With four ambulacra (brissi.) 



Sp. 1. Spatangus pectoralis. Ovato-elliptical, depressed, 

 large ; four ambulacra, with the interstices elegantly granu- 

 lated ; the assulae elongated at the margin. Recent. Seba, 

 Mus. iii. Tab. xiv. fig. 5, 6. 



2. S. ventricosus. Ovate, inflated, obsoletely assulated ; 

 with four oblong canaliculated ambulacra; the larger tu- 

 bercles placed in zig-zag. Recent. 



Brissus ventricosus. Leske ap. Klein, Tab. xxvi. fig. A. 

 An. Scill. Corp. Marin. Tab. iv. fig. 1, 2. 



3. S. purpureus. Cordated ; with four smooth lance- 

 olate ambulacra; the larger tubercles placed in zig-zag. 

 Recent and fossil. 



Spatangus purpureus. Leske ap. Klein, Tab. xliii. 

 fig. 3-5; Tab. xlv. fig. 5. Scill. Corp. Marin. Tab. ii. 

 No. 1. fig. 1. 



4. S. ovatus. Ovate ; semicylindrical ; depressed back- 

 wards, with four excavated canaliculated ambulacra, the 

 fore ones oblique. 



Spatangus brissus unicolor. Leske ap. Klein, Tab. xxvi. 

 fig. B. C. Recent. 



5. S. carinatus. Ovate, inflated, and a little turgid at 

 the sides ; ambulacra four, the fore ones transversely diva- 

 ricated ; the dorsal area carinated backwards, and obtusely 

 projecting. Recent. 



Spatangus brissus, late carinatus. Leske ap. Klein, 

 Tab. xlviii. fig. 4. 5. 



6. S. columbaris. Oval ; vertex depressed ; with four 

 shortish ambulacra, the hinder ones straight. Recent. 

 Seba. Mus. iii. Tab. x. fig. 19. 



