440 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



PELAGODISCUS Dall, uov. sect. 

 Disoinisca atlantica Kino. 



Collected by the " Challenger " expedition, at station 299, off Valparaiso, in 2160 

 fathoms, mud, bottom temperature 34° F. U. S. S. "Albatross," station 4709, 

 southwest of the Galapagos Islands, in 2035 fathoms, temperature 35°.3 F. 



The typical Disciuisca has the distal ends of the brachia coiled, but in this 

 ■widely distributed abyssal form the brachia form two simjile loops with no spiral 

 whatever. The lower valve is very thin and fragile; it is almost impossible to 

 detach it from the animal, owing to the hourglass shape and great solidity of the 

 peduncular muscles. It is smooth and without the concentric or radial sculpture 

 found in the shallow-water species. It is also markedly smaller than the upper 

 valve, and the closely adherent lower half of the mantle bears peripherally only 

 short setae, the very long setae with prickly surfaces, characteristic of this species, 

 are confined to the edge of the upper lobe of the mantle. The rather poorly 

 preserved specimen upon which these observations were made was collected in 

 the North Atlantic, off Martha's Vineyard, by the "Albatross." One young 

 specimen was obtained from the Pacific in the " Albatross " dredgings, on a 

 manganese nodule. 



Craniidae. 



CRANIA Retzius. 



Crania patagonica Dall. 



Crania patagonica Dall, Proe. U. S. Nat. Mas., 1902, 24, p. 662; 1903, 26, p. 950, 

 pi. 62, figs. 1, 3. 



U. S. S. "Albatross," station 2783, west coast of Patagonia, in 122 fathoms, 

 mud, bottom temperature 48° F. U. S. N. Mas. 96,913. 



The single upper valve upon which this species was founded is quite sufficient 

 to distinguish it from any other. No other species of Crania has been described 

 having the upper surface of the valve decorated with little sharp tubercles, which 

 under the lens have the appearance of very short spines. 



In his report of the Bclgica Antarctic expedition brachiopods (Anvers, Dec, 

 1901) Joubiu states that Crania pourtalesii Dall has been reported from Cape 

 Horn, and in fact I find the name cited without comment in the list of species 

 from Cape Horn given by Fischer and Oehlert as collected by the Mission to 

 Cape Horn. "Whether a specimen too imperfect to afford material for study was 

 provisionally referred to the West Indian Crania, or why no further remark was 

 made about it, I am unable to say, but it m.iy have been a specimen or fragment 

 of the present species, as it seems improbable that C. pourtalesii should extend 

 from the tro])ics to the Antarctic. It is quite evident from the rxcclloiit niapnified 

 figure given by Joubin that his Crania lecointei from south latitude 70° 23', in 



