342 Prof. T. R. Jones on 
Although this approaches figs. 10 and 11 in shape, it is 
longer in proportion ; and though somewhat shorter relatively 
than Kolmodin’s figures of LZ. phaseolus (from Hisinger’s 
type specimen), it may really belong to that species. A 
Scandinavian true Z. phaseolus (from Dr. Lindstrém) shows 
a somewhat granulated surface, which, when smoothed down, 
would give the slight reticulation above noticed ; but it has 
no trace of the slight marginal flange existing in our Baltic 
specimen (not shown in the outline) on the front and hinder 
edges, like that seen in Schmidt’s fig. 13, a, of his L. Angelind, 
and more developed than is shown in Kolmodin’s fig. 5, a. 
This variable expression of a feature would scarcely alter the 
specific place of these specimens; and therefore I refer to this 
specimen from Oesel as varietas marginata of Leperditia 
phaseolus (Hisinger). 
Fr. Schmidt’s L. Angelini and its varieties (op. cit. pp. 13, 
14, figs. 18-18) seem to comprise LZ. phaseolus (as both 
ata and Kolmodin surmise) and some closely allied 
orms. 
5, 6, and 7. Leperditia canadensis, Jones, and Leperditia 
fabulites (Conrad), with varieties; and Leperditia amyg- 
dalina, Jones. 
The characteristic features of Leperditia canadensis and its 
varieties are described and illustrated in the Ann. & Mag. 
Nat. Hist. ser. 3, 1858, vol. 1. pp. 244, 840, &e., pl. ix. 
figs. 11-17; and in the Geol. Surv. Canada, decade ii. 1858, 
pp. 92-95, pl. xi. figs. 6-12, 16,17. Its stout little valves, 
with their subquadrate outlines and strong dorsal angles, are 
easily recognized, however much the variability in some re- 
spects affects the surface, margins, and contours. One set, 
however, of the varieties indicated in the above-mentioned 
memoir, namely that typified by var. josephiana, is some- 
what distinct from the others, having the antero-ventral region 
much contracted, and therefore possessing a more elliptical 
and graceful outline than the others. It slightly approaches 
the shape of L. phaseolus, but would more closely represent 
an elliptical, elongate-ovate form of L. balthica, if this were 
taken as the leading type, than any modification of L. Hisin- 
gert, Schmidt, which is characterized by a short hinge-line 
and a very deep and oblique postero-ventral region. 
It is this form, moreover, that seems to have been Mr. 
Conrad’s Cytherina fabulites*, as intimated at page 341, Ann. 
& Mag. Nat. Hist. May 1858, and p. 95, decade ii. Geol. 
Surv. Canada, and further supported by Prof. Safford, of 
* Philadelph. Acad. N. Sci. Proceed. 1843, vol. i. p. 382. 
