THE NAUTILUS. 91 



NOTES ON THE ANATOMY OF STROBILOPS LABTBINTHICA (SAY). 



BY G. DALLAS HANNA. 



(Contribution No. 102, from the California Academj of Sciences.) 

 Several years ago, some examples of Strobilops labyrinthica 

 (Say) were collected alive at Great Falls of the Potomac River, 

 in Virginia, and advantage was taken of the opportunity to as- 

 certain some points regarding the anatomy. Drawings and 

 notes were made at the time of dissection but other activities 

 have prevented their preparation for publication until now. 



The small, ribbed, dome-shaped shells with internal lamellae 

 are common in the eastern part of the United States and their 

 familiar forms need no special mention here. Say described 

 the first species as Helix labyrinthica. (Jbiirn. Phila. Acad, ScL, 

 I, 124, 1817.} Morse in 1864 (Journ. Portland Soc. Nat. Hut., 

 Vol. I. p. 26, 1864) created the genus Strobila for it; but this 

 name, unfortunately, was preoccupied several times. Pilsbry 

 ( Proc. Acad. Nat. Sci, Phila. 1892, p. 403) renamed the group, 

 Strobilops in 1892. (See also in this connection, Pihbry, NAUT., 

 VII, p. 56, 1892. NAUT. XXII, p. 78, 1908. ) According to 

 him the genus is represented by numerous species in the Euro- 

 pean Tertiary from the Eocene; also in America it is found from 

 Maine to Venezuela, west to the Rocky Mountains and possibly 

 it is found on the Galapagos Islands. Several speciea are found 

 in Japan, Eastern Asia and the Philippines. 



A cursory examination reveals the following names which 

 have been applied to American material: labyrinthica (Say) : 

 strebeli (Crosse and Fischer) : virgo (Pilsbry) : affinis Pilsbry: morsei 

 (Dall): salvini (Tristram): hubbardi (A. D. Brown): vendreyeti- 

 ana (Gloyne): texasiana Pilsbry and Ferriss. There may be 

 others. 



The anatomy, Plate 2, figs. 10, 11, indicates that the genus is 

 distinctly Pupillid in its relationships. The kidney, being par- 

 allel to the rectum, separated therefrom and leading directly to 

 the mantle margin, places it in the superfamily or tribe, Orth- 

 urethra Pilsbry. Fundamental shell characters are sufficient to 

 segregate the group as a distinct family, Strobilops-idse. ( When 



