260) New Land Shells from Costa Pica. 
Cryptostrakon Gabbi, n.s. 
(Pl. xi, fig. H.) Animal varying from black to shades of brown, and vari- 
ously mottled with black or dark brown; usualiy a little greenish on the 
shell; darkest posteriorly. Length of dried specimens corresponding to 
size of Dr. Gabb’s figure. 
Internal shell (pl. 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 (pl. xi, fig I). 
Lingual membrane (pl. 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 Blaneo, 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- 
eimens brought by Dr. Gabb, Iam 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., VI, p. 282, 
t. 10, ft. 7. (diamaw, Krynickia, semitectus of same author, 
1857, 1. ¢., p. 841). 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 Lima, and 
the jaw of Lemazx (pl. xi, fig. P). 
The lingual membrane (pl. 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 
