and Species of Crmo'idea. 2(>7 



Genus Echinocrinus, Agassiz, 

 E. spinosus, Austin, sp. 

 Def. — Body conico-globose, with five double rows of ambu- 

 lacral plates, and the like number of interambulacral spaces. 

 The five pairs of avenues run from the mouth to the columnar 

 point of attachment. The ovarian plates surround the mouth 

 instead of the anal opening, as in the recent Echini, but which 

 organ is as yet undiscovered in these fossil animals. The 

 whole surface is covered with spines, but these are of two 

 sorts ; the one kind, though few in number, are long and fur- 

 rowed longitudinally. The prominences near their bases are 

 circular, and in their ends are cup-like excavations by which 

 each one fits on to the tubercle in the centre of each plate. 

 The second sort of spines are short, and are rather numerously 

 but irregularly scattered over the plates and around the cen- 

 tral spine. Column unknown. 



E. anceps, Austin, sp. 



The only part of this species yet discovered is a beautiful 

 fragment showing the internal structure of the ambulacra and 

 a few of the adjoining plates. On showing the specimen to 

 Professor Agassiz some time since, he pronounced it to be the 

 internal surface of a portion of the E. pomum. Though the 

 Professor's name ranks deservedly high in science, and how- 

 ever presumptuous it may appear to dissent from such an 

 authority, we are compelled in this instance to do so, for the 

 following reasons : — the ambulacral pores of the specimen in 

 question are much wider asunder than in the E. pomum, the 

 plates themselves are much larger, and above all, are beyond 

 comparison thinner than in the species Prof. Agassiz assigned 

 them to. 



Since Professor Agassiz saw the specimen in question, we 

 have had many opportunities of examining the internal struc- 

 ture of the E. pomum, and we can find no resemblance what- 

 ever between the two species. 



It appears to us that the name of our genus Sycocrinites 

 and that of the Echinocrinus of Professor Agassiz require 

 amendment, as their terminations imply affinities which do 

 not exist. 



A great majority of the new species defined in the foregoing 

 paper were discovered and collected from the strata in which 

 they occur by the authors. 



Kingsdown, Bristol, January 18, 1813. 



