184 NEW WEST AMERICAN SHELLS DALL. 



posterior ventral angle of the pallial sinus, two small circular impres- 

 sions and some obscure and irregular markings at the entrance of the 

 sinus, all due, doubtless, to attachments of the mantle and probably 

 inconstant or variable in different individuals ; the anterior part of the 

 pallial sinus nearly reaches the scar of the anterior adductor, and nearly 

 the whole of the basal part is coincident with the line of the basal attach- 

 ment of the mantle ; the hinge plate is broad and subtriangular quite 

 strong, bearing one prominent grooved tooth between two channels; 

 behind the posterior channel, in the left valve, is a much narrower, 

 obscure, and little-raised tooth ; the corresponding second tooth in the 

 right valve is anterior and similarly obscure; the left valve is destitute 

 of lateral teeth, but in the right valve there is a short, strong, elevated? 

 subtriangular, anterior lateral close to the anterior cardinal, and a 

 more distant and feeble posterior lateral over the posterior adductor 

 scar, A-ltitude of shell, 28.5 ; maximum longitude, 48; diameter, 8.5 

 millimetres, of which 5.0 millimetres is comprised in the left valve. 



Habitat : Long Beach, San Pedro, California ; first collected by Mrs. 

 G. L. Trowbridge, and forwarded for inspection by Miss Ida Shepard ; 

 subsequently by Mrs. Burton Williamson, of University, California. 

 Catalina Island, 16-38 fathoms ; J. G. Cooper (fragment) and W. H. 

 Dall (young shells). Fossil in the Miocene of San Diego, California. 



This fine shell is a typical Tellina. It is apparently most nearly related 

 to Deshayes' T. denticulata of the Cumiugian collection. His descrip- 

 tion in several jioints, though insufficient for certain identification, 

 agrees fairly well with this species. T. denticulata does not appear to 

 have been figured. The shell, so named by Sowerby in Reeve's Iconica, 

 is a 3Iaco7na, and probably a young specimen of M. secta. It does not 

 agree with Deshayes' description, nor with his MS. outline in my posses- 

 sion. The species is not referred to by Bertin, in his revision of the 

 TelLinidw of the Paris Museum, and I have been unable to consult 

 Romer's monograph. There is nothing corresponding to the present 

 shell in Reeve's or Hanley's monograph. The shell referred by Car- 

 penter (Mazatlan Catalogue, p. 38) to Deshayes' species is worn and not 

 capable of being positively identified, while the habitat of Deshayes' 

 type is unknown. Two specimens forwarded by Mrs. Williamson differ 

 quite markedly in height from base to beaks. One, which Mrs. William- 

 son kindly presented to the Museum, was an almost perfect match for 

 the specimen forwarded by Miss Shepard which is figured herewith ; 

 the other was proportionately less elevated. 



Mr. Edgar A. Smith, Assistant in the British Museum, in charge of the 

 conchological collections, after comparing the drawings here used to 

 illustrate this species with Deshayes' type in the British Museum, and 

 with their other Tellinidw, writes of Deshayes' form : "It is evidently 

 quite distinct from your shell, which I can not identify with anything 

 in our collection." A sketch of Deshayes' shell, kindly made and sent 

 by Mr, Smith, fully confirms his opinion of their distinctness, T. denticu- 



