DALL: MOLLUSCA AND BRACHIOPODA. 431 
Cetoconcha smithii Dar, n. sp. 
Plate 18, figure 10. 
Shell extremely thin, subequivalve, inequilateral, oval, white, with a very thin, 
dehiscent, pale brownish periostracum ; hinge 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 45 of the whole length behind 
the anterior end; valves evenly convex, polished, with minute radialing lines 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 
hinge 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. 8, “ Albatross,” station 3415, off Acapulco, Mexico, in 1879 fathoms, 
globigerina ooze, bottom temperature 86° 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 Datu. 
Cetoconcha scapha Dart, Proc. U. S. Nat. Mus., 1902, 24, p. 561; 1903, 26, p. 951, 
pl. 62, fig. 13. 
U.S. S. “ Albatross,” station 3367, 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. 
CUSPIDARIA NARDO. 
Nardo’s genus dates from 1840, but ten years earlier Wilton had figured in 
the Quarterly Philosophical Journal (p. 73) a valve of a fossil bivalve apparently 
elonging to this genus, to which he gave the generic name Ryderia. Curiously 
enough, he did not name the species, and the generie 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. 
Juspidaria s.s. 
Cuspidaria patagonica Smith, 
Neaera patagonica E. A. Smith, Challenger Rept., 1885, Lam., p. 39, pl. 7, fig. 5, 
ba-b, 
Cuspidaria patagonica (anatomy) Dall, Bull. Mus. Comp. Zoöl., 1889, 18, pp. 443, 
447. 
