DALL: MOLLUSCA AND BRACHIOPODA. 225 
of California; off the coast of Peru, Scammon. Also off Acapulco, Mexico, at 
station 3422, U. 8.8. “ Albatross.” 
This beautiful and 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 Datt. 
Argonauta pacifica Dall, Amer. Nat., 1869, 3, p. 287; Amer. Jour. Conch.; 1871, 7, 
p. 95; Hoyle, Cat. Rec. Ceph., 1886, p. (213) 9. 
2 Argonauta argo Reeve, Conch. Icon. Argonauta, 1861, pl. 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 the 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 compressa 
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 and the Azazs groups the presence or absence 
of auriculation is not a specific character. Some species appear to be always 
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 RECENT ARGONAUTS. 
Group or A. Arco. 
Aperture simple. 
A. Argonauta grandiformis Prrrr. 
VOL. XLIII. — NO. 6 15 
