New Land Shells From Costa Lrcu. 2Qd9 
right of the mantle margin, slightly in advance of the centre: genital and 
anal orifices—? * 
Shell internal (pl. xi, fig. J) rudimentary, unguiform, large, membranous, 
protected by an epidermis?, without distinct septa, a spiral arrangement, 
indicated above by depressed lines, below by raised ridges. 
_ daw (pl. xi, fig. I) high, solid, decidedly arched, ends scarcely attenuated; 
anterior surface with a few stout ribs, denticulating the lower margin. 
Lingual membrane (pl. xi, fig. K) as usual in Polygyra, Stenotrema, &c. 
Long and narrow. Central teeth tricuspid, laterals bicnspid; marginals 
quadrate, irregularly bicuspid, the inner cutting points the larger and 
bifid. 
Known only by C. Gabbi, described below. 
This curious slug may at once be distinguished from all 
others by its rudimentary shell, entirely concealed by the 
mantle, and of about similar size. The shell has no distinct 
whorls, but a spiral arrangement is indicated on the upper sur- 
face by impressed lines, on the lower surfece by a raised spiral 
ridge. The edge of this ridge is reflected, in dried specimens, 
for about one-half whorl, giving a Haliotis-like character to 
the shell. The shells of Mariella, Geotis, and Parmella are 
somewhat similar to this, but those genera differ widely in 
their other characters, especially the jaw and lingual dentition. 
Indeed, there is no known slug combining all the generic 
characters of this, so that I am forced to suggest a generic 
name. ; 
The dried animal reminds me of Sempe.’s figure (Phil. 
Arch.) of dried Vitrinopsis, on account of the small size of 
the dried body compared to that of the shell. 
* Animal limaciforme, subcylindricum, postice attenuatum. Pallium sab- 
centrale, tenue, paululum anterior, parvum, ovatum, testam includens. 
Discus gressorius? Porus mucosus nullus. Apertura respiratoria ad dex- 
tram pallii in parte vix anteriori marginis Apertura genitalis et analis—? 
Testa interna, magna, membranacea, (epidermide protecta?) unguiformis 
paucispira. 
Maxilla solida, valde arcuata, costis paucis validis exarata. 
Lamina lingualis ut in Polygyra, Stenotrema, &¢. Dentes centrales tricus- 
pidatz, laterales bicuspidate, marginales quadrate, irregulariter lonettierpucl 
ate, papillis internis seo els) bifidis. 
