Canada 
Geological Survey 
Victoria Memorial Museum 
BULLETIN No. 1 
II. — Note on Merocrinus Walcott . 
By F. A. BatheBj D.Sc., F.R.S., British Museum (Nat. Hist.) 
(Published by permission of the Trustees of the British Museum.) 
Perhaps the interpretation of Ottawacrinus proposed in the 
preceding paper may be extended to the allied genus Merocrinus 
and its Monocyclic isomorph Iocrinus. I have always been 
dissatisfied with the usual interpretation of those genera. If in 
them the gabled plate supporting the anal tube be not a brachial 
(and few have been found to admit this as a possible inter- 
pretation), then it must be the superradial; but this makes the 
r. post. R very different from all the other radials, and in quite 
an unusual way. If, however, the elements in the four other 
rays, usually regarded as IBri, were really Rs, then all the 
radials would have the same composition, just as they have in 
Ottawacrinus . It would then no longer be said (as in “Treaties 
on Zoology, Eehinoderma,” p. 179) “These two genera [Mero- 
crinus and Ottawacrinus] suggest that RA of Dicyclica may not 
be strictly homologous with RA of Monocyclica,” 
The interpretation here suggested would result in the fol- 
lowing — 
Diagnosis of Merocrinus Walcott. — A Dendrocrinid with 
5 IBB ; with RR transversely bisected, and all Ri equal in size 
and shape and alternating with BB ; with anal x resting on the 
left shoulder of r. post. Rs, and supporting a median series of 
plates. 
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