dall: mollusca and brachiopoda. 431 



Cetoconcha smithii Dall, n. sp. 



Plate 18, flsnre 10. 



Shell extremely tliin, subequivalve, inequilateral, oval, white, with a very thin, 

 dehiscent, pale brownisli periostracuni ; hiuge consisting of a minute obsolete 

 tubercle in the right valve and two small, narrow nymphs bearing a slight, short 

 ligament ; beaks low, slightly prosococlous, situated -^^ of the whole length behind 

 the anterior end; valves evenly convex, pohshcd, with minute radial iug Hues of 

 microscopic granules which are most apparent near the posterior end, but can be 

 traced over the entire surface ; ends of the shell of about equal rotundity, base 

 evenly arcuate, margins entire; interior polished, the muscular scars hardly visi- 

 ble. Lon. 19.0; alt. 14.0; of beaks, 1.5 ; diam. 11.0 mm. The right posterior 

 hiuge margin, bordered by a closely adjacent radial ridge, slightly overlies the 

 margin of the opposite valve along a length of about 7.0 mm. 



U. S. S. " Albatross," station 3415, off Acapulco, Mexico, in 1879 fathoms, 

 globigerina ooze, bottom temperature 36° F. U. S. N. Mus. 122,943- 



Named in honor of the ever courteous and accomplished Mr. E. A. Smith of 

 the British Museum of Natural History. 



Cetoconcha scapha Dall. 



Cetoconcha scapha Dall, Proc. U. S. Nat. Mus., 1902, 24, p. 561 ; 1003, 26, p. 951, 

 pi. 62, fig. 13. 



U. S. S. "Albatross," station 33G7, Gulf of Panama, in 100 fathoms, rocky 

 bottom, temperature 57° F. U. S. N. Mus. 109,026. 



A single specimen only was obtained. It is smaller, more elongate and arcuate 

 than the C. smithii. 



Cuspidariidae. 



CrSPlDARIA Nardo. 



Nardo's genus dates from 1S40, but ten years earlier Wilton had figured in 

 the Quarterly Philosophical Journal (p. 73) a valve of a fossd bivalve apparently 

 belonging to this genus, to which he gave the generic name Ryderia. Curiously 

 enough, he did not name the species, and the generic name therefore was in the 

 condition of having no named type or species belonging to it, which under the 

 rules would appear to render the name Ryderia futile. 



dispidarla s. ». 

 Cuspidaria patagonica Smith. 



Neaera patagonica E. A. Smith, Cliallciiper Rept., 1885, Lam., p. 39, pi. 7, f5g. 6, 



5a-b. 

 Cuspidaria patagonica (anatomy) Dall, Bull. Mus. Comp. Zool., 1889, 18, pp. 443, 



447. 



