DALL: MOLLUSCA AND BRACHIOPODA. 411 



TELEODESMACEA. 

 (Diogenodonta). 



Astartacea. 

 Astartidae. 

 ASTARTE SowERBY. 

 Astarte longirostra Orbignt. 



Falkland Islands, Orbigny, Straits of Magellan, U. S. S. " Albatross," at 

 station 2778, in 61 fathoms, bottom temperature 48° F. U. S. N. Mus. 110, 

 711. Elsewhere in depths as little as 20 fathoms, but rare apparently everywhere. 



The variations of this shell are considerable. Orbigny figured one with excep- 

 tionally long umboues, and the more common mutation with shorter beaks has 

 received the name of A. magellanica from E. A. Smith. 



Cyrenacea. 

 CORNEOCYCLAS Ferussac. 



Corneocjidas Ferussac, ex parte, Diet. Sci. Nat., 1818, 12, p, 278 ; Dall, Trans. 



Wagner Inst. Sci., 1903, 3, p. 1459. 

 Pisidium C. Pfeiffer, Naturg. Conch., 1821, 1, p. 123. 



Corneocyclas magellanicus Dall, n. sp. 



Shell small, whitish, with an olivaceous smooth periostracum, low, wide beaks, 

 and polished surface with faint concentric indications of three or four resting 

 stages ; form inequilateral, anterior end shorter, bluntly subtruncatc ; base 

 evenly rounded ; posterior end slightly attenuated and rounded ; external sculp- 

 ture of faint incremental lines, chiefly obsolete between the resting stages; in- 

 terior smooth, white ; hinge of right valve with a single feeble horizontal tooth 

 directly under the beak, and two well-developed lateral teeth rather distant from 

 the beak, tlie posterior lateral stronger. Length of shell, 3.5 ; of posterior end of 

 shell, 1.8 ; heigiit, 2.5 ; diameter (of both valves), 2.0 mm. 



U. S. S. "Albatross," station 2778, in Magellan Straits, iu 61 fathoms; one 

 right valve. 



A single right valve, evidently washed into the sea from some stream, was 

 obtained as above. As no species of tiiis genus has been reported from this 

 region I have thought it best to put it on record. The beak is not in any way 

 differentiated or set off from the general surface of the shell. 



