New and Little Known American Paleozotc Ostracoda. 181 
Variety INSIGNIS, n. var. 
Plate Xf, fae. 1%, 
Associated with hundreds of the typical form of this species, as 
described above, I find two specimens differing from the usual 
forms in one respect only. Namely, in having a transverse ridge 
or crest-like elevation a little in front of the center of the valves. 
This feature causes the variety to resemble 7. cristata, Whitfield 
sp., but the shape of the valves of that species is different, they 
being shorter with the posterior margin more oblique. 
f. ottawa, Jones, has the ends more equal, the extremities of the 
hinge distinctly angular, and is without the depression in the dorsal 
slope. J. gracilis, Jones, likewise has the dorsal angles sharper, 
and the posterior end more truncate. Both of these species have 
a row of minute pits along the ventral edge, a feature not noticed 
in /. amiana.* 
Position and locality: This species is very abundant on the bed- 
planes of an erratic block of limestone, found by Mr. H. M. Ami, 
of the Geological survey of Canada, in Sussex street, Ottawa, and 
supposed to belong to an upper member of the Chazy group. Part 
of this block was kindly given to me by Mr. Ami. 
Part II. 
UPPER SILURIAN AND DEVONIAN SPECIES. 
LEPERDITIA (?) SUBROTUNDA, DN. Sp. 
MENG, ALES. 1, a, 0, 6: i 
Size of left valve: Length, 0.85 mm.; height, 0.68 mm.; thick- 
ness, 0.21 mm. 
Carapace small, short, rounded, uniformly convex, encircled, 
except at the strongly convex ventral edge, by a flattened border, 
widest in the postero-dorsal region. Dorsal edge scarcely straight, 

* Since the above was written I have received from Prof. T. Rupert Jones 
proofs of two plates which have been prepared for the Geological Survey of 
Canada. On plate X I notice figs. loa and 11a because I am satisfied that 
they have been drawn from specimens of J. amzana. These figures are 
marked ‘‘ /. ottawa, variety,’’ but, for the reasons stated above, I cannot 
accept this designation for my specimens. 
