416 Bibliographical Notices. 



(i.) Subfamily El^acrinid^, E. & C. 

 EJa'acrinus, Roemer. 



(ii.) Subfamily Schizoblastid^, E. & C. 



ScJiizoblastus, E. & C. Cri/ptoblastiis, E. & C. 



Acentrotremites, E. & C. 



4tb Family. Granatoblastid^, E. & C. 



Calyx globular or ovoidal, with flattened or concave base and 

 linear ambulacra. Spiracles five, piercing the deltoids ; or ten, 

 grooving their lateral edges. 



Granatocrinus, Troost. Ileterohlastus, E. & C. 



oth Family. Codasterid^, E. &C. 



Base usuallj' well developed and sometimes very long. Some, or 

 all of the hydrospire-slits pierce the calyx-plates on the sides of the 

 radial sinus, restricted portions of which may remain open as the 

 spiracles. 



(i.) Subfamily PniENOscHisMiD^, E. & C. 

 Codaster, McCoy. Phcenoscliisma, E. & C. 



(ii.) Subfamily CrtptoschismidjE, E. & C. 

 Oropliocrinus, von Seebach. CryptoscMsma, E. & C. 



Order IRREGULAUES, E. & C. 



Unstalked Blastoids, in which one ambulacrum and the corre- 

 sponding radial are different from their fellows. Ease usually 

 uusymmetrical. 



6th Family. Astrockinid^, T. &T. Austin 

 (emend. E, & C). 



(i) Basals unsymmetrical. Azygos radial small and without 

 definite limbs ; its ambulacrum short, wide, and horizontal. 



Astrocrinus, T. & T. Austin. 

 EleutJierocrinus, Shumard & Yandell. 



(ii) Basals symmetrical ; odd ambulacrum linear. 

 Pente-pJiyllum, Haughton. 



The authors state that there is no certain evidence of the existence 

 of true Blastoids anterior to the Upper Silurian period ; and the 

 type appears to have become extinct long before the close of the 



