DESCRIPTIONS OF THE SPECIES. 223 



lineatus (P\. XVII. fig. 18), a peculiarity which we have nol noticed in any othei 

 Blastoid. S. Sayi is further remarkable for having as manj as eighty side plates 

 which leave a considerable portion of the lancet-plate uncovered in the middle line 

 of the ambulacrum (PI. 111. fig. 3). S. melonoides has about fifty, and S. Rofei 

 from twenty to thirty, which approach one another rather closely (PI. VIII. fig. II). 

 This is the only species in which we have distinctly seen the outer side plates. 



Species. The number of species which we can refer to Schizoblastus is smaller now 

 than when we first defined the genus ; for a personal acquaintance with some of the 

 American species which we formerly only knew from figures and descriptions has 

 shown ns that they belong to other generic types. 

 The species of Schizoblastus now recognized by us are as follows : — 

 Schizoblastus Bailii, sp. nov. Carboniferous Limestone; Ireland. 

 Granatocrinus melonoides, M. & W. Burlington Limestone, Subcarboniferous ; 



Iowa. 

 Granatocrinus Rofei, E. & C. Carboniferous Limestone ; Ireland. 

 Pentremites Sag/, O. & S. Burlington Limestone, Subcarboniferous ; Iowa. 

 In addition to these, any one of the following species may be a Schizoblastus 

 though we suspect that some of them would be more properly classed with Crypto- 

 blast us or Mesoblastus. 



Granatocrinus granulosus, M. & W. Keokuk Group, Subcarboniferous ; 



Illinois and Indiana. 

 Granatocrinus lotoblastus, White. Burlington Group?, Subcarboniferous; 



Arizona. 

 Granatocrinus neglectus, M. & W. Burlington Group, Subcarboniferous; 



Iowa. 

 Pentremites Missouriensis, Shumard. Chemung Group, Upper Devonian l ; 



Missouri. 

 Pent remit, s Potteri, Hambach 2 . Burlington Group, Subcarboniferous; Iowa. 

 Granatocrinus project us, M. & W. Burlington Group, Subcarboniferous; 



Iowa. 

 Pentremites Sampsoni, Hambach. Kinderhook Group, Subcarboniferous; 



Missouri . 

 Granatocrinus Shumardi, M. & W. Burlington Group, Subcarboniferous ; 

 Iowa. 



Distribution. The two Irish species of Schizoblastus both occur in the Carboni- 

 ferous Limestone ; while S. melonoides and S. Sayi are limited to the Burlington 

 Group in the Mississippi Valley Series of the American Subcarboniferous. Tin-, 



1 According to S. A. Miller this species belongs to the middle or upper part of the Subcarboniferous. 

 - We do not think that this species is anything more than a small form of S. Sayi. 



