A MONOGRAPH OF THE EXISTING CRINOIDS 13 



Bathymetra (genotype Antedon abyssicola P. H. Carpenter, 1888) including 



Bathymefra abyssicola. Bathymetra carpenteri. 



Bathymetra brevicirra. Bathymetra minutissima. 



Hypalometra (genotype Antedon dejecta P. H. Carpenter, 1888) including 



Hypalometra dejecta. 



Isometra (genotype Antedon lineata P. H. Carpenter, 1888 [ = Antedon angusti- 

 pinna P. H. Carpenter, 1888]) including — ■ 



Isometra angustipinna. 



Nomina nuda given in the preceding lists are — 



Ollgometra caribbea. Trichometra vexator. 



Thaumatomeira comaster. Bathymetra brevicirra. 



Thaumatometra parva. Bathymetra carpenteri. 



Iridometra crispa. Bathymetra minutissima. 



Trichometra aspera. 

 and further on in the paper 



Eudiocrinus variegatus. 



The new name Coccometra nigrolineata was also used. This name had been 

 applied (in MS.) to a species from the West Indies represented by a number of 

 specimens in the National Museum collections to which H. L. Clark's specimen of 

 Antedon hagenii from Porto Rico belonged. 



The new genus Pentametrocrinus was proposed to include all the described 

 species of Eudiocrinus except E. indivisus, E. granulatus, and E. variegatus, and the 

 following species were assigned to it : 



Pentametrocrinus atlaniicus. Pentametrocrinus semperi. 



Pentametrocrinus japonicus. Pentametrocrinus tuberculatus. 



Pentametrocrinus varians. 



Pentametrocrinus was found to be closely related to Decametrocrinus and the 

 two were united in the family Pentametrocrinidae, to which Thaumatocrinus was also 

 added. 



Eudiocrinus indivisus, E. granulatus, and E. variegatus were found to be related to 

 the species of Zygometra, and Eudiocrinus was placed with Zygometra in the family 

 Zygometridae. 



The proximal arm structure of Eudiocrinus, Pentametrocrinus, and Uintacrinus 

 was discussed in detail, and the costals (IIBr series) of the comatulids were said to be 

 merely repetitions of the first two brachials of the free arms interpolated between 

 the regular first brachials and the radials; the distichals (IIIBr) and palmars (IVBr) 

 are additional reduplications of the first two brachials, either single (2) or double 

 (4 [3+4] or 4 [1+2; 3 + 4]). 



