: 266 Wachsmuth and Springer—Silurian Crinords. 
basals, often well developed; its strongly marked _ bilateral 
symmetry ; and by its ten primary arms as arule. It is typi- 
fied by Reteocrinus O'Nealli, R. cognatus, R. gracilis, R. stellaris, 
R. fimbriatus ; while R. Richardsoni, R. Beri, R. subglobosus 
and R. Pattersoni—the latter described by Miller as a Glypto- 
crinus, Cincinn. Journ., July, 1882—are good examples of it in 
every respect, except that the underbasals have not as yet been 
noticed, and perhaps do not exist; although we think it very 
probable that they may be found to possess these plates in a 
more or less rudimentary form as in Glyptocrinus. We do not 
consider it necessary or advisable to separate these species from 
the typical form upon this character alone, since the whole 
assemblage of species above named forms a group, which i 
united by other well defined characters. The slight modifica- 
tion of our statement of generic characters renders it easy and 
figures, extended down to the bas If it has in fact four 
basals, it would be a good Mariacrinus, were it not for the posi- 
t first anal plate, which is not in contact with the 
basals in any of the Melocrinites ; or it would have the calycal 
Glyptasterites, without however ahy development of under- 
asals. The other species for which Miller has established a 
2 
enus, and in case the Gl. Harrist should prove to possess 4. 
quadripartite base, and the discovery of other specimens shows 
this character to be constant, we should be disposed to adopt 
the same course with that form. 
