THE NAUTILUS. 81 



Fifteen and twenty years ago, in this vicinity, I found re- 

 peatedly a form which then was taken for one of the color vari- 

 ations of P. caroliniensis, although averaging larger, and unfor- 

 tunately and stupidly I did not examine it exactly. Some 

 time ago one specimen of exactly the same was found, with 

 about a dozen caroliniensis, as described by Binney and W. G. 

 Binney. It was evident at first sight that the animal is of a 

 distinct species, and it may be one of those named by Rafin- 

 esque, as mentioned in W. G. Binney, Man. Amer. Land Shells, 

 p. 247, but I have not the literature for comparing. In order 

 to have a designation, it may be named biseriatus, provisionally 

 the specimen was 70 mm. long when fully extended. The 

 color, over most of the back, is brownish, not grayish, some- 

 what irregularly mottled, and not sharply defined towards the 

 margins. On the back there are two parallel series of 10-12 

 irregular black spots, streak-like when the animal is fully ex- 

 tended, the largest in the middle, evanescent towards the an- 

 terior and posterior ends. Irregularly distributed, mainly 

 along the outer side of each series are irregular "white" spots; 

 that is, they appear whitish, but the ground color is a pale tan, 

 and there are small dots, rather granules, of a glistening bluish 

 white, and such dots are also distributed over the balance of the 

 mantle surface. On each side, between the series of black apots 

 and the lateral margin, there is another series of slightly marked, 

 cloudy, dark spots, some of them barely visible. The sole is 

 whitish without any color tinge, while in caroliniensis it has a 

 rusty tinge from minute dots of that color, especially along the 

 margins. Along the middle, mostly in the posterior part, there 

 is an obscure line of dark, as it is also in caroliniensis and some 

 other snails. The head and the posterior end of the foot are 

 somewhat slate-colored, the eye peduncles darker. The whole 

 body is different in appearance from that of caroliniensis, and 

 somewhat more translucent. 



This description may be imperfect, but I believe that any 

 specimens of the same kind will be readily recognized from it. 

 While the genital organs of two P. caroliniensis, of the same size, 

 were fully developed, those of " biseriatvs " will still quite rudi- 

 mentary, and nothing could be made out of them. The jaw 



