254 F. Stoliczka — Notes on Terrestrial Mollusca. [No. 3, 



ous gland (jag) of moderate size, slightly thickened ; hermaphro- 

 dite gland (Jig) large, rather flatly depressed, connected with 

 the uterus by a long twisted duct (M). The vas deferens (jpd) 

 branches off a short distance from the hermaphrodite opening ; 

 in about three-fifths of its length from its origin it has a long pointed 

 appendage (cp) t consisting of strong tissue, filled with minute, 

 elliptical, calcareous secretions ; this appendage is attached by a 

 special muscle close to the place of attachment of the arrow sac ; 

 the last two-fifths of the vas deferens gradually widens, and towards 

 the end the simple tube consists internally of remarkably soft, 

 muscular tissue, but there is no papilla present. The receptacu- 

 lum seminis (Vs.) is a globular gland, attached to along, slightly 

 twisted string, originating from the oviduct, quite*close to the 

 hermaphrodite opening. 



I may here record an observation, which I have repeatedly made 

 viz., that there is a very great difficulty in tracing spermatozoa in 

 the hermaphrodite gland. Eggs are certainly formed there, but 

 they further develop to an appreciable size in the uterus, into 

 which the necessary amount of albumen is supplied from the 

 albuminous gland. Spermatozoa I could not, in this case, detect in 

 the hermaphrodite gland ; they must be of extreme minuteness, 

 but they become fully developed in the hermaphrodite duct or 

 string {hd) ; in fact this duct almost entirely consists of spermatozoa 

 in nearly all terrestrial Mollusca which I have examined. 



The jaw of S. calias is broadly semilunar, thin, apparently 

 smooth, but when moderately enlarged and viewed in transparent 

 light, a distinct concentric striation is perceptible and there are 

 also some very minute radiating lines to be observed near the 

 middle part. A fringe of muscular tissue is attached to the convex 

 side, the concave margin is usually entire, but in one instance 

 (see pi. xix, fig. 3 a), I observed a very distinctly developed pro- 

 jection in the middle ; this example is taken from the var. schistos- 

 telis, but other specimens of the same variety, and equally large, did 

 not possess it. The jaws of S. discoidalis and conjungens are similar 

 to those of calias ■, only differing very slightly in shape ; in both 

 there is a small projection at the centre of the concave margin, and 

 both are also finely concentrically striated, like the jaw of S. calias. 



