the Morphology of the Blastoidea. 239 



American species referred to Granatocrinus^ as G. melo and 

 G. Sai/i, have ten notches in tlie sides of the oral ])lates,. 

 instead of pores, and will constitute our genus Schizohlastus. 



The species forming Granafocrinas so emended are ^ the 

 foUowinir : — 



o 



I. Tijjjical Sjyecies. 



G. Norwoodi, 0. & S. Burlington Limestone (Sub- 

 carbon iferous) , lo vva. 

 G. ellijyti'cus, Phill. Carboniferous Limestone, England. 



G. derbiensisj Phill. ,, „ ,, 



G. orbicularis J Phill. ,, „ ,, 



G. campanulatuSj M^Coy. „ „ ,, 



^ G. pistfbrijus, sp. nov. ,, ,, ,, 



G. 21%'oi/i, sp. nov. „ ,, ,, 



IL Aberrant and Doubtful Species. 

 G. elongatus, Phill. ; G. liofii^ sp. nov. Both from the 

 Carboniferous Limestone. 



The form and general appearance of the calyx presents a 

 remarkable uniformity of type throughout the species which 

 we have restricted under the name of Granatocrinus. Two 

 broad divisions may be traced — the lirst after the type of G. 

 Norwoodi^ the second after that of G. ellipticus. In the first 

 the form is subglobose ; and, includes all the British species 

 except the one named. The latter forms a division of itself 

 and is elongately elliptical. 



Tiie summit is more or less flattened in all, or even at times 

 a little depressed. The base is usually small, flattened^ or 

 concave, ilie amount of the concavity varying according to 

 species, the basal plates never being visible \n a side view : 

 in Q. Norwoodi it is narrow and deej), in G. orbicularis 

 broad and shallow, the same in G. ellipticus, rather deeper in 

 G. derbiensis, broad and almost flat in G. canipanulatus, in 

 fact broader in this species than in any other. 



The proportions of the radial and oral plates of GranatC' 

 crinus vary considerably ; some species have large radials 

 and small orals, others small radials and large orals. Generic 

 subdivision has before now been attempted according to the 

 relative sizes of these plates ; but, as Messrs. Meek and 

 W'orthen have very justly observed, speaking of tiie orals in 

 particular, " there are so many gradations in this character, 

 liowever, that it does not seem to be possible to make it a 

 means of separating the species into two well-defined sec- 

 * These will be deserib,.cl in our more exteudod work on the Blastoidea. 



