1893.] NATURAL SCIENCES OF PHILADELPHIA. 237 



The liver in pulchella and other species is light yellow, normally, 

 but lighter or darker brown in some specimens. The latter color I 

 first thought to be caused by certain kinds of food, or by a certain 

 stage of digestion, but it lasted for several days, and even weeks, 

 during which the snails were confined and apparently not feeding, 

 therefore too long to admit of this explanation. It is probable 

 that the deeper coloration is caused by a degeneration, or incipient 

 decomposition of the organ due to old age, as I have seen it in 

 dead as well as in living specimens of this and other species and 

 genera of land shells. Observations in this line, checked by 

 microscopic examinations, should be made on Vallonia and other 

 forms. 



The ovotestis is extended all along the liver, up to the apex, 

 making numerous intersections. The ganglia were not examined 

 thoroughly. They seem to be of a somewhat peculiar type. In V. 

 parvula (and other species) the cervical masses are adjacent to each 

 other in nearly their entire length, and from these short commis- 

 sures are seen to be closely connected, probably visceral ganglia on 

 either side, while from the latter, long commissures extend to the pedal 

 ganglia respectively. These are of the form figured by Leidy in 

 Binney's Terr. Moll. I, PI. IX, f. vii (of V. pulchella). The rather 

 large, pear-shaped stomato-gastric ganglia are not adjacent to each 

 other. It may be added that [ found parasitic worms, such as 

 probably infest all mollusca, in a half grown V. pulchella; there 

 were several comparatively large species. 



The jaw is more or less arcuate, about 4-6 times wider than high 

 (in V. pulchella, e.g. 0*23 wide, 0"064 high) rounded or slightly 

 angular at the ends, comparatively strong and partly of deep horn 

 or chestnut color in some ; thin, flexible and pale in others (e. g. in 

 perspectiva and albula). The coloration is always deepest in the 

 inferior part, gradually fading from about the middle upward, so 

 that the superior edge is nearly or quite colorless. Sometimes it has 

 a slight, wide median projection to the cutting edge, as in V. excen- 

 trica (Plate VIII, fig. M), and as also indicated by Moquin-Tandon 

 for V. pulchella. If this character be constant in excentrica, we 

 must suppose that the French author chanced to examine an exam- 

 ple of this species, which is widely distributed over Europe and has 

 been confounded with pulchella. The anterior surface is somewhat 

 convex perpendicularly, as seen in figs. K and L, PI. VIII, and 

 bears more or less fine and crowded ribs, about 18-25 in number, 



