204 PROCEEDINGS OF THE ACADEMY OF 



Dr. Bridges announced the death of Mr. Chas. McEuen, late a mem- 

 ber of the Academy. 



Dr. Leidj called the attention of the members to a bottle containing numerous 

 specimens of a large species of Gordius discovered by Dr. Wra. A. Hammond, 

 525 miles west of Fort Riley, Kansas Territory. Dr. Hammond states they were 

 found in a pond in great numbers, in company with Siredon. They swam ac- 

 tively forward an inch or two beneath the surface of the water, and occasionally 

 lifted the anterior end even above the latter. 



The collection contains 24 females and the same number of males. The 

 females are cylindrical, light brown of various shades, shining, iridescent ; an- 

 terior extremity narrowed ; head surrounded with a dark brown ring ; tail ob- 

 tuse, slightly compressed, with a terminal genital pore The males are darker 

 colored than the females ; tail extremity more or less spirally enrolled, with the 

 extremity bifurcated ; forks divergent, incurved, smooth, connected at base 

 anteriorly by a crescentic fold, in advance of which is the genital pore ; head 

 as in the female. 



The females measure from 10 inches in length by ^ of a line thick, to 2 feet 

 6 inches in length and 3-5ths of a line thick ; the males 8 inches in length by \ of 

 a line thick, to 2 feet 2 inches in length by 2-5ths of a line thick. 



Dr. Leidy next directed the attention of the members to a bottle containing 

 seven specimens of the larva of a species of Oestrus or bot-fly. They were ob- 

 tained by Dr. Hammond from a pouched rat, Thomomys borealis, at Bridger's 

 Pass, on the summit of the Rocky Mountains, July 1857. Dr. Hammond found 

 the rat panting on the road side, without power of escaping. The bots were 

 found situated beneath the skin of the back, belly, and thigh. 



The body of these larvoB is oblong oval, compressed, incurved ; head minute, 

 composed of a transverse pair of papillary eminences, each supporting two minute 

 ocelli, and having j^rojecting from beneath, forward and downward, a pair of 

 strong black hooks. Spiracular lamina trilobed and marked with vermicular 

 lines. Segments of the body closely covered with discoidal corneous tubercles, 

 of which the anterior ones have their posterior border projecting and dentated. 



The smallest is light yellowish brown ; and as they become larger they assume 

 a darker tint. The largest are black, hard, shining and remarkably shagreened 

 in appearance. 



Length of the smallest larva 5 lines, breadth 3 lines, thickness 2^ lines ; length 

 of largest 9 lines, breadth 5^ lines, thickness 3 lines. 



December StJi, 1857. 

 Vice-President Bridges in the Chair. 



Dr. Leidy called the attention of the members to a drawing of a curious 

 animalcule, found attached to stones and dead stems of plants in the Delaware 

 and Schuylkill rivers. The animal, though closely allied in structure to the 

 Rotatoria or wheel animalcules, yet possesses no rotary or other ciliated apparatus. 

 The body is regularly oval, transparent, colorless, and finely tuberculated. From 

 the anterior truncated extreniitj^ of the body, the animal projects and retracts at 

 will a delicate cup-shaped membrane about half the size of the body. The 

 membrane exhibits delicate and distant longitudinal and circular muscular 

 fibres, which are branching. At the bottom of the cup the mouth communicates 

 with a capacious stomach, and this with a muscular gizzard with lateral jaws, as 

 in most rotifers, and which, as in these, are constantly in motion. From the 

 gizzard opens a second stomach, Avhich communicates with a short intestine 

 terminating in a posterior anal aperture. The digestive apparatus is attached 

 to the outer tunic of the body by diverging muscles. The visceral cavity usuall}- 

 contains numerous eggs in various stages of develoi)ment, from that containing 

 the germinal vesicle to such as contain the fully formed ennbryos. Attached 

 to the inner surface of the body are a number of opaqne, white, irregularly oval 

 bodies. 



[December, 



