pall: mollusca and brachiopoda. 225 



of California ; off the coast of Peru, Scammon. Also off Acapulco, ^Mexico, at 

 statiou 3422, U. S. S. "Albatross." 



This beautiful aud very distinct little species is widely distributed. It is prob- 

 able that the reference by von Martens of this species to a form of argo is due 

 rather to the very poor figures of Reeve and Sowerby than to actual inspection of 

 specimens, as with the latter under one's eyes any specific connection with the 

 argo type is seen at once to be inadmissible. Dunker has given an admirable 

 figure in his Novitates. 



The material obtained, as above, by the " Albatross," in all cases was fragment- 

 ary, though enough to identify the species, which is represented in the National 

 Museum by other well-preserved specimens. 



Argonauta pacifica Dall. 



Argonauta pacifica Dall, Amer. Nat., 1869, 3, p. 237 ; Amer. Jour. Conch., 1871, 7, 



p. 95; Hoyle, Cat. Rec. Ceph., 1886, p. (213) 9. 

 ? Argonauta argo Reeve, Conch. Icon. Argonauta, 1861, pi. 3, fig. 2 d. 



Monterey, California, southward to the Gulf of California. U. S. S. " Albatross," 

 stations 3365, 3374, 3389, and 3400, in the Gulf of Panama and near the Gala- 

 pagos Islands ; fragments. 



It was with some hesitation that I separated this form from the Mediterranean 

 A. argo (L.) Blainville, and tiie reasons which led to the decision are mentioned 

 in the American Journal of Conchology. I have seen much more dry material 

 since that time, all of which is fairly uniform. The specimens are invariably 

 rounder, wider, and shorter than those from the Mediterranean, and the auricles 

 tend more outward. The figures of Reeve and Sowerby representing compresna 

 Blainville and argo all show a greater space in the lateral sinuses than I have seen 

 in any actual specimen of either. It is probable that further study of the animal 

 will be required to decide the standing of the nominal species of the argo group. 

 It seems almost certain that specimens from the Mediterranean, Antilles, and the 

 west coast of America never attain the size of the oriental compressa. But it is 

 also practically certain that in this aud the hians groups the presence or absence 

 of auriculation is not a specific character. Some species appear to be alwavs 

 auriculate, others always without these projections, while others again have an 

 auriculate and a simple form with intermediate gradations occasionally. 



As there seems to be no recent summary of the species of Argonauts I have 

 prepared one. 



SUMMARY OF EECENT ARGONAUTS. 



Grodp of a. aroo. 



Aperture simple. 



A. Argonauta grandiformis Pbrht. 



VOL. XLIII. — MO. G 15 



