34 



Spatangites bicordatus, Tab. XLVII. .F^. 6, Lesk. In this fossil, which 

 is but rarely met with, there exist, connected by a linear carinated 

 ridge, two vertices, in which the ambulacra terminate. Both ends, thus 

 becoming sulcated, the echinite is said to be bicordated. 



Spatangites carinatus, Tab. LI. Fig. 2, 3, Led-. This Spatangite, like 

 the former, has a linear carinated ridge, connecting two vertices ; but, 

 unlike the former, the narrow anal termination is not sulcated. It is 

 also figured by Baier, Oryct. Noric. Tab. in. /. 43. 



The third family of this genus is considered by Leske as composed 

 of those echini which form the genus Brissus*, of Klein : the chief cha- 

 racters of which are : the back not grooved but striated ; four deep cre- 

 nated and perforated sulci, as ambulacra ; the base tumid ; the anus and 

 mouth patulous, and the latter bilabiated. None of the varieties of Spa- 

 tangus brissus, into which, according to Leske, they all resolve, appear 

 to be known in a mineralized state. 



The genus brissoides, of Klein, is adopted by Leske as the fourth 

 family of Spatangi. The shells of this family, like the brissi, are ovate, 

 and the back striated, but not lacunated ; the rays are flat. 



Spatangus brissoides, Tab. xxvn. B. Klein, is ovate, oblong, subcord- 

 ated; with four petaloidal, lanceolated ambulacra, with two rows of 

 pores, connected by transverse striae ; large tubercles existing between 

 the ambulacra ; the rest of the surface being covered by granulated risings. 

 The mouth subrotund and renifbrm, surrounded by pores disposed in the 

 form of a pentagonal star ; the middle of the base raised and tuber- 

 culated. 



Spatangus ovatus, Tab. XLIX. Fig. 12, 13, Lesk. differs from the for- 

 mer, chiefly in being more convex ; but this species does not appear to 

 be known fossil. 



Spatangites ovalis, Tab. XLI. Fig. 5, Lesk. copied from Walch, Tab. 



* Brissus. This word, fyiccras, is applied by Aristotle, and after him by Athenaeus, to 

 certain genera of echini. The name Brittus is also elsewhere applied to them. Afyvros is 

 the designation, then, of a genus of echini, corrupted from ufyuroi, i. e. non commcsu apti. 



