174 NEW WEST AMERICAN SHELLS DALL. 



Eupleuia niuricifoimis Broderip. 



(Plate V, Fijr. 2.) 



lianelln muriciformh Rrod., P. Z. S., 18:52, p. 179; Reeve, Couch. Icon. Iianella,F\g.^i. 

 JiitncUa plicata Reeve, P. Z. S., 1844, p. V.\S ; Couch. Icou., Fi<f. '3.1. 

 IiUiulla triquctra Reeve, op. cit., p. 139; Couch. Icon., Fig. 41, 1S44. 

 Eupleura muriciformis Dall, Trans. Wajjner Inst. Sci., Hi, p. 145, 1890. 



Habitat : Montija Bay, West Columbia, Camlwg fide Broderip ; San 

 Diego, Nuttall, Jide Reeve ; oft" (Jerros Island, Lower Califoruia, in It) to 

 16 fathoms; U. S. Fish Commission. 



This species is found lis'inj^' in the Pacific waters from Venezuehi to 

 California and fossil in the Postpliocene of much of the same region. 



E. triqnetra Reeve is a large specimen with an unlinished lip ; E. 

 plicata of the same author is evidently a specimen of the same form 

 with the canal shortened by mutilation. 



I have seen no connecting links with E. pectinata Hinds, though they 

 may exist. E. nitida Broderip is an entirely distinct species. 



There are three varieties in the recent material belonging to this 

 species which 1 have examined. The adult typical muriciformis has 

 the following characters ; 



On the last whorl there are three strong knobs between the varices 

 on each side; there is a thin, webbed varix with six primary spines, all 

 recurved and deeply grooved in front; within the aperture there is a 

 dentiform callus on the outer lip between every pair of spines and one 

 on each side of the sutural commissure; the spine at the shoulder is 

 much the longest, but the second si)ine, counting forward, is the one 

 corresponding to the axis of the intervarical nodes; the web between 

 the shoulder sj)ine and the suture is bent forward; the spirals corre- 

 sponding to the si)ines are very coarse, but not much elevated, and be- 

 come stronger anteriorly as the spines diminish in strength and length. 



The shell averages 37.4 millinjetres in length, 23.5 millimetres in 

 breadth, with a lesser diameter of about 12.2 millimetres. 



Eupleura (var ?) uuispinosa Dall. 

 (Plate vr, Fig. 5.) 



Eupleura muriciformis Brod., var. uHispinom Dall, Trans. Wagn. Inst., iir, p. 146, 1890. 



This variety was collected by liich at Mazatlan. It has a thick varix, 

 hardly webbed, with only one short, recurved spine, which is at the 

 shoulder; a much recurved canal ; a subtriangular section ; and, owing 

 to the absence of webbing and spines, api)ears especially slender. This 

 is the form which in my rei)ort on the Blake Gastroi>ods (A, p. 203) 

 was (;ontrasted with the typical E. caudata. 



The sj)ecim«'n figured has a total length of 33.3 millimetres, a maxi- 

 mum breadth of IG, and a sectional lesser diameter of 13 millinjetres. 

 This form is quite thick conipared with the ty[)e and perhaps should 

 be regarded as a distinct species, but these forms are so variable that 

 1 hesitate to separate them. 



