no. 1826. MOLLUSKS OF THE GENUS BITTIUM— BARTSCH. 385 



Three, B. armillatum, purpureum, and vancouverense, are placed 

 here with some doubt because the nuclear whorls are somewhat worn 

 and it is barely possible that they may possess sculpture when 

 perfect. 



Lirobittium has nine forms on the west coast. Of these, two only 

 are placed here of which I have not seen the nucleus in perfect condi- 

 tion, namely, B. (L.) munitum Carpenter and B. larum Bartsch. 

 However, since B. (L.) munitum munitoides Bartsch belongs here, 

 there can scarcely be any doubt about placing munitum in this posi- 

 tion. 



The species of Lirobittium are: 



interfossum Carpenter. munitum munitoide Bartsch. 



catalinense Bartsch. asperum Gabb. 



catalinense inornatum Bartsch. asperum Xomaense Bartsch. 



ornatissimum Bartsch. cerralvoense Bartsch. 



munitum Carpenter. larum Bartsch. 



Of the following seven species, I have not seen the nuclear whorls • 

 their subgeneric position must, therefore, remain doubtful until more 

 perfect material has been examined. They will probably prove to be 

 Semibittium or Lirobittium. 



oldroydee Bartsch. giganteum Bartsch. 



fetellum Bartsch. casmaliense Bartsch. 



decussatum Carpenter. arnoldi Bartsch. 



Five species, Bittium (Stylidium) eschricTitii, Bittium catalinense, 

 Bittium catalinense inornatum, Bittium attenuatum , and Bittium quadri- 

 filatum, occur both recent and fossil. The first, Bittium (Stylidium) 

 eschrichtii, has been reported by Doctor Dall ' from Fossil Rock at 

 Coos Bay, Oregon (Pliocene), but so far has not been found fossil in 

 any Pleistocene strata. 



Bittium catalinense Bartsch is known from the Lower Pleistocene of 

 Santa Barbara and San Pedro (Lower San Pedro series), and is found 

 living in rather deep water. The subspecies Bittium catalinense 

 inornatum Bartsch is known from the Lower Pleistocene of San Diego 

 and recent. Bittium attenuatum Carpenter is the most abundant 

 recent Bittium and has been found fossil in the Lower San Pedro 

 Series at San Pedro (Pleistocene). Bittium quadrifilatum Carpenter 

 is a common recent species also found in the Lower Pleistocene of 

 Santa Barbara, California. 



Of the seven species known as fossils only, Bittium casmaliense 

 Bartsch and Bittium arnoldi Bartsch are from the Lower Pliocene of 

 Santa Barbara County, California, while Bittium asperum Gabb has 



i Prof. Paper 59, U. S. Geol. Surv., 1909, p. 76. 

 80796°— ProcN.M. vol. 40— 11 25 



