432 DR F. A. BATHER. 



covered ? The former view is that of Dr Jaekel ; the latter is that which I have 

 maintained. 



§ 274. Dr Jaekel has divided the remainder of his Callocystidae into SubfaniiUes 

 that correspond fairly with the lines of evolution indicated by me in 1900 (p. 61). To 

 discuss these in detail would be too far from the subject of this memoir, but I may be 

 allowed to state my position briefly. The separation of Callocystis, Sphaerocystis, 

 Strohilocystis (overlooked by Jaekel), and Coelocystis, founded in 1903 by Schuchert, 

 is natural and may be convenient. They form the Subfamily Callocystinae. 



§ 275. To adopt Staurocystis Haeckel for Pseudocrinus quadrifasciatus may be 

 justified, and it is tempting to continue to mark its resemblance to the restricted 

 Pseudocrinus, by placing the two genera in an independent Subfamily. But if this 

 were done, it would scarcely be consistent to leave Lepadocrinus (syn. Apiocystites) 

 in the same Subfamily as Lepadocystis (syn. Meekocystis). Such multiplication of 

 Subfamilies, even if justified on speculative grounds, is certainly of no practical con- 

 venience. Therefore I prefer to retain all these genera in one Subfamily. For this 

 neither of Jaekel's names will serve, since Staurocystinae is manifestly inappropriate, 

 and Apiocystinae cannot be used if Apiocystis is a synonym of Lepadocrinus. There- 

 fore the name Lepadocystinae is retained. 



§ 276. We come, at last, to those genera which I have assembled in the Subfamily 

 Glyptocystinae, viz. Glyptocystis, Cheirocrinus, Pleurocystis, and Cystohlastus, 

 In the first place, the Subfamily may be raised to the rank of a Family, so as to 

 correspond with the Echinoencrinidae and Callocystidae. But, since Dr Jaekel has 

 placed each of those genera in a separate Family, one should perhaps consider whether 

 all should properly remain in a single Family, or, if so, whether that Family should 

 be subdivided. 



§ 277. Glyptocystis has already been discussed (§ 273), and, if it is to be moved 

 from the Callocystidae (sensu Jaekel), it must certainly be placed very close to 

 Cheirocrinus. 



§ 278. Pleurocystis, it is true, looks very different from Cheirocrinus, and Dr 

 -Jaekel in his phylogenetic tree (1899, p. 174) has derived it, not directly from Cheiro- 

 crinus, but from his Scoliocystidae ( = Echinoencrinidae). On the other hand, he has 

 himself emphasised the close relations of the oldest species of Pleurocystis to Cheiro- 

 crinus (pp. 231, 232, 233, and 234), and apparently would infer that Pleurocystis has 

 arisen as a natural modification of the Cheirocrinus plan of structure. It seems to 

 me that, if the distinction between the two be marked by making Pleurocystis an 

 independent genus, so their connection should be indicated by placing both in the 

 same Family. 



§ 279. The structure of the remaining genus Cystohlastus has been independently 

 analysed by Dr Jaekel (1899, p. 233) and myself (1900, p. 66) in the same manner, 

 and as a natural result we are agreed upon its relations to Cheirocrinus. Dr Jaekel, 

 however, believes that Cystohlastus is a link between Cheirocrinus and the Blastoidea, 



