260 New Land Shells from Costa Rica. 



Cryptostrakon Gabbi, n. s. 



(PI. xi, fig. H.) Animal varying from black to shades of brown, and vari- 

 ously mottled with black or dark brown; usually a little greenish on the 

 shell; darkest posteriorly. Length of dried specimens corresponding to 

 size of Dr. Gabb's figure. 



Internal shell (pi. xi, fig. J) rudimentary, about 14 mill, in greatest 

 length; with concentric lines of growth; very membranous; about two 

 whorls are indicated (see generic description). 



Jaw strongly arcuate, ends blunt, but little attenuated ; anterior surface 

 with two stout decided ribs, denticulating either margin, and several other 

 subobsolete ribs (pi. xi, fig I). 



Lingual membrane (pi. xi, fig. K) long and narrow. Teeth 52-1-52, with 

 22 laterals, the 23d tooth having its inner -cutting point bifid. Marginals 

 low, wide, with one inner, long, wide, oblique, bluntly bifid cutting point, 

 and one outer, short cutting point. 



Locality, Flanks of Pico Blanco, 5000-7000 feet elevation. 



Limax semitectus, Morch? 



Plate xi, fig. O, is copied from an original drawing by Dr. 

 Gabb, of a slug found by him on plantain leaves and stalks at 

 Borubeta on the Uren, Costa Rica, altitude 2500 feet. From 

 his notes it appears that the color is dark brownish-green; no 

 spots ; generally wrinkled. Length 0.7 inch. Head slender 

 and projecting considerably beyond the mantle; tail very 

 short, barely perceptible under the mantle. From dried spe- 

 cimens brought by Dr. Gabb, I am confident that the mantle 

 and orifice of respiration are as given by me in fig. O. The 

 size of the mantle suggests the identity of the slug with Limax 

 (Megapelta) semitectus, Morch, Jour. Conch., YI, p. 282, 

 t. 10, f. 7. (Limax, LTrynicMa, semitectus of same author, 

 1857, 1. c, p. 341). From the specimens preserved in spirits, 

 I cannot detect the orifice of respiration, but evidently there 

 is a locomotive disk, an internal shell like that of Limax, and 

 the jaw of Limax (pi. xi, fig. P). . 



The lingual membrane (pi. xi, fig. Q) is long and narrow. 

 There are 44-1-44: teeth. The centrals have side cusps and 

 cutting points. The laterals, 12 in number on each side of the 

 central, are bicuspid ; the marginals are aculeate, all of them 



