72 Hill I. UN 82, I M I KD STATES NATIONAL MUSEUM 



DETAILS OF ARM STRUCTURE 



In his report upon a mass of dissociated comatulid ossicles from the Eocene 

 (Middle Jaoksonian) at Baldook, Barnwell County, S. C, Professor Gislen took 

 OCOaaioD to classify the types of arm ramification found in the comatulids, both recent 

 and fossil. He distinguished 85 typos, which ho analyzed in detail on the basis of 

 available data taken from previously recorded specimens. He also reviewed with 

 greal oare such of the structural features of the Himerometridae as would be of 

 importance is the determination of dissociated fragments. 



From these dissociated ossicles he reconstructed Himerometra bassleri, sp. 

 dot ., most closely related to the recent H. persica, which is interesting in being the 

 only representative of the family Himerometridae that has been found in America. 



From the same material he also segregated fragments that he referred to Micro- 

 crinus cf. eonoideus Emmons and to Qlenotremites (Paleantedon) carolinianus, sp. 



IKIV. 



TYPES OF ARM BRANCHING IN THE COMATULIDS 



Dr. Gialeo has ili\i<lod the arm branching in the comatulids into 85 types, which 

 are (omitting those found only in fossil forms) as follows: 



(2) Eudiocrinus typo {Eudiocrinus only). (3) Pentametrocrinus type (Pentametro- 

 crinus ami Atopocrvnus). (4) Thaumatocrinus type (same as the preceding, but with 

 10 radials). (7) Comatula pectinata type (10-armed species of Comatula, and Coma- 

 tulilla). (8) Zygometra prisiiua type (Zygometra pristina and 10-armed young of 

 Zygoirutra and Catoptometra). (9) Antedon type (the majority of comatulids). (10) 

 Monaehometra fragUis type I. (11) Promachocrinus type (Promachocrinus only). 

 (15) Comatula rotatoria type {Comatula rotalaria only). (16) Comatella maculata 

 typo. (17) Neocomaiella pulclolla type I. (18) Neocomatella alata type. (19) 

 Comatella brachycirra type. (20) Asterornetra type. (21) Stenometra diadema type. 

 (22) Monaehometra jragilis type II. (23) Diodontometra type. (25) Catoptometra 

 rubroflava type. (26) Catoptometra hartlaubi type I. (27) Perissometra macilenta 

 t \ i m ■ . (28) Pachylornetra anguslicalyx type. (29) Heterometra bengalensis type. (30) 

 Comanthus solaster type. (31) Adelometra angustiradia type. (32) Crinometra imbri- 

 rata typo. (32a) The abnormal Comanthoides spanoschistum type. (33) Capillaster 

 coccodistoma type. (34) Nemaster discoidea type. (35) Heterometra compta type. 

 .7 Comatella stelligera type. (38) Catoptometra magnifica minor type. (39) Neo- 

 comati lln pulehella typo II. (40) Crinometra concinna type. (41) Stylometra spinifera 

 type. (42) Stephanometra spicata type. (43) Mariametra subcarinata type. (44) 

 Comanthua parvicirra type I. (45) Comaster serrata type. (46) Crossometra sep- 

 tentrionalia type (47) Zygometra comata type. (4S) Heterometra crenulata type. 

 ' lantheria r<>tula type. (50) Oceanometra magna type. (51) Comanthus 

 japonic* type. ' I morensis type I. (53) Himerometra martensi type. 



Crinometra transversa typo. (55) Catoptometra hartlaubi type II. (56) Coman- 

 thus parvicirra type II. (57) Comanthus timorensis type II. (58) Crinometra in- 

 iculpta type. (59) Heterometra nematodon type. (60) The irregular Comanthus 

 timorensis type 111. (61) Nemaster grandis type. (62) Capillaster multiradiata 

 type. (63) Capillaster macrobrachius type. (64) Capillaster mariae type. (65) 



aster gracUit type I (66) Comatella nigra type. (67) Catoptometra magnifica 

 type. (68) Oxymetra i type. (69) Pontiomdra andtrsoni type. (70) Coman- 



