264 PROCEEDINGS OF THE ACADEMY OF [1893. 



what thin and flexible, with rather crowded, strong, irregular rib- 

 stria?, evanescent toward the upper and strongly denticulating the 

 cutting edge ; the posterior duplicative appears also rather thin and 

 soft ; PI. VIII, fig. O, shows it extended by pressure. 



I could not measure exactly the length of the radula nor count 

 the transverse rows in the specimen examined ; it is 0'27 mm. wide. 

 Formula R : 4+2 : 10 (11) ; there are, consequently, 33 (35) teeth, 

 the highest number seen in a Vallonia. The central tooth is of 

 common shape, rather wide but not much wider posteriorly, its 

 lateral edges curved up for the most part of their length. On the 

 4 perfect laterals the cusps are stout ; the fifth and sixth are transi- 

 tion teeth having a smaller though distinct plate, but with hardly 

 projecting posterior distal angle. Their inesodonts are marked 

 of the formation pointed out in the general description, while the 

 ectodonts are simple in most, finely two-pointed in some inter- 

 spersed teeth. Of all laterals the ectodonts are larger than the same 

 in V. costata. The marginals are as usual, but with comparatively 

 few cusps. The seventh tooth from the center is a true marginal in 

 its whole configuration, though with only 2-3 short distal cusps ; 

 here the transition from laterals to marginals is more abrupt than in 

 any other species seen. The last marginals (1-2) are quite small 

 and with hardly any perceptible cusps. 



The shell is related on one side to costata, on the other to cyclo- 

 j)horella, and seems to be intermediate. It resembles the latter in 

 its size and general appearance, the umbilicus being rather wide 

 and considerably expanding for the last i whorl, the latter distinctly 

 ascending before descending ; in the fine dense ribs, which are 

 stronger and sharper on the shell itself and bear smaller mem- 

 branes than in costata and in the coloration. It has, however, some 

 features allying it to costata — the aperture although less trans- 

 versely elongated, is not circular. The presence of a lip is charac- 

 teristic, and the peristome is rather abruptly and strongly everted, as 

 in costata. These characters, together with the formation of the jaw 

 and radula place this Vallonia in a peculiar position. I regard it 

 as a distinct species, for which I propose the name albula, because 

 of its whitish shell. 



Mr. Geo. W. Taylor, of Victoria, B. C, sent me recently a few 

 Vallonia for examination, among which there was one specimen 

 from the Rocky Mountains, B. C, resembling in size and shape the 

 Quebec specimens, although it was weathered and had lost its epi- 



