PACIFIC COAST SPECIES. 97 



ducts (7, 7) enter; from this the stomach passes into the intestine (8), 

 which proceeds first forward almost to the cesophagus, thence pro- 

 ceeds backward to the extreme rear of the general cavity of the body, 

 and again forward to below the respiratory cavitj'^, into which it pene- 

 trates upwards as the rectum (9), and through which it passes to the 

 anus, whose position is described above. The intestine in its whole 

 course winds among, and is imbedded in, the various lobes of the liver, 

 which latter organ is arranged as usual in Limax, Arion, &c. 



In A. Californicus (Plate XI, Fig. E, 1. c.) there is a difference in the 

 arrangement of the stomach. Before reaching the cul-de-sac (6) the 

 stomach is greatly constricted, and the cul-de-sac runs at right angles 

 with the stomach in an erect position, not lying on its side, as I have 

 represented it, in order to show the connection between it and the 

 anterioi" portion of the stomach, which connection was entirely con- 

 cealed by the cul-de-sac in its upright position. The extreme length 

 of the digestive system is three times that of the whole body of the 

 animal, at least in its contracted state. 



Tbe jaw in all the forms of ArioUmax is quite thick, dark horn-col- 

 ored, arcuate; ends but little attenuated, blunt; anterior surface with 

 stout ribs, denticulating either margin. I have figured (p. 93) the jaw 

 of A. Columbianus, which has about 18 ribs (another specimen had 12). 

 In A. Californicus, from Mr. Anthony, there were 13 ribs to the jaw; 

 14 in Mr. Hemphill's specimen of the same. In A. niger Dr. Cooper 

 describes about 20, but in one specimen I found but 8. In A. Hemp- 

 Mlli I found 8-12 ribs; in A. Andersoni, 13 ribs. 



The pouch of the lingual membrane is shown in Plate II, Fig. D, 5 

 (1. c). The membrane is, as usual in the Selicidce, with tricuspid cen- 

 tral, bicuspid lateral, and quadrate marginal teeth, showing simply 

 a modification of the laterals. In Land and Fresh-Water Shells, I, p. 

 280, 1 have figured the lingual membrane of the true northern A. Co- 

 lumbianus, which has the general arrangement of Patula. (See also 

 Plate V, Fig. E, Terr. Moll., V.) The marginal teeth are shown to 

 have one long denticle and a small, subobsolete side denticle. This 

 form of marginal teeth I have found also in one of Dr. Cooper's tyi)es 

 of A. niger (Plate V, Fig. D), and in A. Californicus (Plate V, Fig. F); 

 also in A. Andersoni f (Fig. G) and J.. HempUlli (Fig. H). This form 

 of marginal tooth may therefore be considered characteristic of the 

 genus, though in one specimen, supposed to be A. niger, I noticed 



marginal teeth with the outer cusp much more developed and bifid, 

 1749— Bull. 28 7 



