232 



TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Internal plate of 

 A. Columbianus. 



Limax Columbianus, Gould in Terr. Moll., II. 43, PI. LXVI. Fig. 1 (1851) ; 

 U. S. Expl. Exped. Moll., 3, Fig. 1, a, & (1852). — Tryon, Am. Journ. Conch., 

 Fig. 129. HI. 315 (1868). 



Ariolimax Columbianus, MoRCH, Mai. Blatt, VI. 110. — W. G. 

 Binney, Am. Journ. Conch., I. 48, PL VI. Figs. 11-13; 

 L. & Fr.-W. Sh., I. p. 279, Fig. 499 (1869). 

 Internal shell longer than broad, hexagonal, ends pointed. 

 Specimens referred to this species have been found in Wash- 

 ington Territory, Oregon, and California (Straits of Fuca to 

 Santa Barbara, Cooper). It therefore inhabits the Pacific Region. 

 In form, marking, and coloring it may be compared to 

 Arion empiricorum of Europe. 

 Dr. Cooper remarks : — 



" This large slug abounds in the dense damp forests near the Pacific Coast, 

 and was not observed by me in the dry region east of the Cascade Mountains. 

 It is to be found every month of the year in Washington Territory, being even 

 more abundant in the rainy winter than in warmer seasons ; its activity being 

 checked only by extreme cold, while it cannot bear continued drought. It not 

 unfrequently drops from the trees, etc. This slug grows to the length of six 

 inches, but shrinks to a third of that size in alcohol. Its surface is smooth, not 

 rugose, when alive, as represented in Dr. Binney's plate, and its color is a pale 

 yellowish-olive, usually more or less blotched with black." (Pac. R. R. Rep. 

 p. 377.) 



Jaw narrow, arcuate, dark horn or reddish ; anterior surface with more than 

 15 coarse, crowded ribs, denticulating the concave margin (Fig. 128). 

 Lingual membrane (see p. 231). 



On PL XII. Fig. C, I have figured the genitalia of A. Columbianus, which has 

 a very large ovary against which the testicle lies, as in the following species. 

 The ovary is so large as to take up one half of the entire visceral cavity, ex- 

 tending completely across the body, resting on the floor of the 

 cavity, its ends recurved upwards so as to rest upon the liver 

 on the upper surface of the viscera. The body of the animal 

 externally is swollen by the large size of the ovary. The 

 oviduct is narrow, long, greatly convoluted, ending in an ex- 

 tremely long, convoluted vagina. The genital bladder is oval, 

 large, with a short, stout duct. The vas deferens, unlike that 

 of the following form, is as usual in the land shells. It enters 

 the penis at its summit, opposite the retractor muscle. The sac of the penis 

 is very stout, long, cylindrical. The external orifice is described above. 

 The caudal mucus pore described on p. 230 is here figured. 



Fig. 130. 



Caudal pore of 

 A. Columbianus. 



Ariolimax Californicus, J. G. Cooper. 



External characters resembling very nearly those of A. Columbianus, but 

 differing in the genitalia. 



