212 Mr. O. Thomas o?i 



Dall, from near Bird Island, in the mid- Pacific, and C. pata- 

 gonica, Dall, from the coast of Chile and the Straits of 

 Magellan. It was at first suspected that in view of tlie 

 several species of brachiopods leported as common to tlie 

 west coast of North America and Japan, C. caHfornica and 

 C. japoidca might prove to be somewhat near akin, whereas 

 in tact thtiv seem to belong to different subgenera, or even 

 genera. Mr. Hirase's specimens of the latter species were 

 taken at Hirado, Province of Hizen, Japan. 



The nomenclature pertaining to the rather complex tojio- 

 graphy of the interior of the valves in this group of brachiopods 

 does not appear to be in very satisfactory condition in the 

 literature, nor to be any too well correlated with that for the 

 remainder of the animal's anatomy. Bi'ing in no position at 

 the moment to initiate a serious attempt at a remedv, I have 

 in this paper simply taken matters as I found them, and 

 endeavoured to make the be.>t ol' it. 



Unfortunately some details, such as the central nipple-like 

 prominence, are not brought out very plainly in the figures. 



EXPLANATION OF PLATE XL 



Fig. L Crania californica, sp. n. Exterior of dorsal valve, x 3. 



Fig. 2. Ditto. Interior of dorsal valve, with the dried animal in situ, 



X 3. 

 Fig. 3. Ditto. Interior of dorsal valve, after removal of the animal, x 3. 



The figures are from photographs by Berton W. Crandall. 



XXI. — The '■'■ Huron ^^ of the Argentine. 

 By Oldfield Thomas. 



(Published by permission of the Trustees of the British Museum.) 



While working out the San Juan iiuron, Grisonella, re- 

 ferred to in a succeeding paper, I have come to the conclusion 

 tiiat my reference of the common huron of the Argentine to 

 the Brazilian Grisonella fxirax caTinot be sustained. When 

 making it, material of the Argentine form was much less 

 abundant than now, while, especially, I then supposed that a 

 specimen in the Museum, no. 44. 3. 7. 6, labelled " Brazil, 

 purchased of Clausen," was of too doubtful authenticity to 

 be taken as of any value. But I now know that this speci- 

 men was one of a series collected in 31inas Geraes (probably 



