A NEW SPECIES OF BATHYTOMA 



FROM THE UPPER PLEISTOCENE OF 



SAN PEDRO, CAL. 



By Prof. J. J. Rivers. 



The photo.s^raph represents two examples selected from 

 six discovered by Dr. F. C. Clark, who has been for several 

 years an investigator of the coast species of both fossil and 

 recent Mollusca. 



Dr. Clark and myself have a partnership in Paleontology, 

 each holding equal rights under the firm name of "Rivers & 

 Clark." We have done no business transactions. Dr. Clark 

 does most of the excavating of Strata, while I have the delight 

 to nominate the species when I am able, but there is such a 

 bulk of material that neither of the compact can resolve satis- 

 factorily. Our material is great, and unless we can obtain 

 the assistance of Dr. Dall of the Smithsonian Institution, years 

 will elapse before a complete catalogue will be forthcoming. 



The photos submited to you have also been sent to the 

 scrutinv of Dr. R. H. Tremper of Ontario, and his reply reads 

 thus: '"The photo is very interesting. I suspect your shell 

 represents some extinct form of Bathytoma. I have not seen 

 a specimen of this genus so long as, nor so attenuate. Your 

 fossil is not B. Tremperana of Dall. The latter is a very dif- 

 ferent shell and very much smaller, good sized specimens 

 measuring 67 mm; body whorl 32 mm, spire 35 mm, making 

 the body whorl shorter than the spire, while in your speci- 

 men the bodv whorl measures 68 mm and the spire 48 mm 

 (if restored)." 



Bathytoma Clarkiana Rivers. I name this in honor of 

 my colleague. Dr. F. C Clark of Santa Monica, Cal. 



The fossil is heavily charged throughout the whole of its 

 structure with carbonate of lime. The columella is thicker 

 than in any described species. If the shell be placed with its 

 aoerture downwards, many concologists would have an 

 opinion that it must be a species of Exotic Mitra. But there 

 are none of the known species of Bathytoma that represents 

 this form in its attenuate outline. This figure will explain the 

 oblique condition of the sutures that divide the whorls. The 

 sculpture has mostly been eroded, but in parts the sculpture 

 represents the true features of the genus. 



Bathytoma Clarkiana Rivers restored measures 116 mm 

 over all, the body whorl measuring 68 mm, the spire 48 mm. 



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