938 The American Naturalist. [October, 
immunized horse to be of practical value to those who are exposed to 
the bites of venomous snakes. It remains now to discover the chem- 
ical constituents of the antivenine, so that it may be manufactured in 
such quantities as to reduce its cost. (Knowledge, Aug., 1895). 
Dall on the Lamellibranchiata.—In his contributions to the 
Tertiary Fauna of Florida, Part III, Dr. Dall adopts a new classifica- 
tion of the Pelecypoda for which he claims the merit that the groups 
are comparably defined. The general features of the system proposed 
by the author in 1889 have been revised, and form the basis of the one 
now offered. As a matter of convenience, the division Pleoconcha 
made by Neumayer to contain certain synthetic types is retained for a 
temporary resting place until more 3 known of these undifferentiated 
ancient forms. 
For the present, then, the class is divided into the following groups, 
of which the third represents the most perfected (although not always 
the most specialized) modern type of Pelecypoda. 
Order Prionodesmacea containing 34 families grouped under 10 
superfamilies. Order Anomalodesmacea, 15 families under 3 super- 
families. Order Teleodesmacea, 46 families under 18 superfamilies. 
The Palsoconcha, 11 families. 
Under each family is an enumeration of the chief generic groups be- 
lieved to be referable to it. 
The genus Solemya Lamark, in this new classification, is placed with 
the Prionodesmacea. (Trans. Wagner Free Institute, ITI, Pt. 3, 1875). 
On the Species of Uma and Xantusia.—In Tare NATURAL- 
ist for 1894, p. 434, I gave descriptions of the two species of Uma 
known to me at that time. An examination of the material in the 
U.S. National Museum has revealed two additional species, which I 
describe below. The U. rufopunctata is based on nine specimens, of 
which seven are from Arizona, where they were obtained by Dr. E. A. 
Mearns, U.S. A. The U. inornata is represented by a single specimen 
(No. 16,500), from the Colorado Desert, San Diego Co., Cal., from Mr. 
C. R. Orcutt. 
I. Black crescents on the throat, and a black spot on each side of the 
belly. 
: Labial scales strongly keeled, six keeled suborbital scales; eight 
loreal rows; hind-foot shorter, one-third head and body ; femoral pores 
40-50; dorsal spots black ; U. scoparia Cope. 
_ IL. Black spots on side of belly, but no crescents on throat. 
