74 PROCEEDINGS OF THE ACADEMY OF 



Prof. Leidy exhibited a fossil which had been submitted to his examination 

 by Prof. Hayden, who obtained it on the Moreau River, a tributary of the 

 Upper Missouri, and was probably derived from the cretaceous formation. 

 The specimen consists of the body of a vertebra of a saurian, devoid of the 

 neural arch, which was separated at the suture. It bears a resemblance to 

 the corresponding part of Notkosaurus, a saurian of the triassic deposits of 

 Europe. The body is cylindroid, moderately narrowed towards the middle, 

 and has the articular ends slightly concave. The sutural connection of the 

 neural arch, including transverse processes, extends some distance down the 

 sides. The measurements of the specimen are as follow : Length of body in- 

 feriorly, llj lines; superiorly, I inch; depth in front, 11 lines; width, 10 

 lines. 



The specimen probahly indicates a marine saurian allied to Nothosaurus, 

 and from its resemblance, the auimal to which it belonged may be named 

 Nothosaurops occiduus. 



July 26th. 

 The President, Dr. Ruschenberger, in the Chair. 



Ten members present. 



On favorable report of the Committees, the following papers were 

 ordered to be printed : 



Descriptions of GRASSHOPPERS, from Colorado. 

 BY PROF. CYRUS THOMAS. 



ANABRUS, Hald. 



The characters of this genus were not fully given by Prof. Haldeman when 

 he established it, and those subsequently added by Girard are scarcely suffi- 

 cient to distinguish it from other closely allied genera. Having both sexes" of 

 three species, I give the following as the principle characters that distinguish 



it. 



Gen. Char. Head large, smooth, advanced in front between the antennas. 

 Pronotum selliform, extending over the base of the abdomen ; rounded and 

 smooth ; anterior portion of the sides reaching below the eyes ; posterior 

 margin and angles rounded. Prosternum bidentate ; posterior angles of the 

 meso-sternum elevated and acute. Elytra very short, having the form of 

 scales in the males ; covered by the pronotum in the females. Antennas longer 

 than the body, sometimes extendiug beyond the ovipositor. Eyes ovate. 

 Labrum round. Maxillary palpi twice the length of the labial ; three outer 

 joints nearly equal ; terminal enlarged at the tip. Abdomen stout, moderate 

 length ; the sub-anal plate of the male large, slightly notched at the tip, 

 furnished laterally with filiform appendages which appear to be articulated 

 at the base ; the cerci (or subsituted appendages) sub-cylindrical, enlarged 

 and generally bifurcate at the extremity. Ovipositor long, bent beyond the 

 middle. Cerci, in the female, small, generally hairy. Legs slender ; posterior 

 pair ver3 r long, femora enlarged next the body, but slender and straight be- 

 yond the middle, as long as the body (omitting the head) ; posterior tibia: 

 long as the femora, slender; all the tibiae provided with four rows of spines, 

 the anterior rows often scattered and apparently irregular. A stout denti- 

 culoid process above the anterior coxa. The tarsi broad, soles concave ; 

 third articulation cordate. 



This genus differs so slightly, in description, from Thyreonotus, Scrv., that 

 there is scarcely a necessity for its retention. But an examination of the 



[July, 



