6 RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 



ganizatioii appears to be intermediate between Ccrcaria scminis and 

 Fdaria. Its varied form and movements are curious to observe ; at 

 one moment globular, then oval, ovate, fusiform, sigmoid, crescentic, 

 &c., it appears as if it would outvie the kaleidoscope in its changes. 

 The motions are vibratile, rotary, with a lateral progression, or 

 whirling in circles like the insect Gyriims. 



Cryptobia helicis might be confounded with the spermatozoa of the 

 animal in which they are parasitic, on account of the organ in which 

 they are found being connected with the generative apparatus, and 

 its supposed use as a spermatheca, but they may be readily dis- 

 tinguished ; the spermatozoa of Helices generally having either a 

 uniform sigmoid or a beaded body, with an enormous proportionate 

 length of tail, and a slow, vibratile motion. It may be well to men- 

 tion that C. helicis does not exist in the collapsed state of the gen- 

 erative organs. 



[Some of the principal forms of the animal are represented in a 

 sketch.] 



[October, 1846. No. 11, See Bibliogvaphy.] 



Dr. Leidy stated that he had lately detected the existence of an 

 Entozoon in the superficial part of the extensor nui.scles of the thigh 

 of a hog. The Entozoon is a minute, coiled worm, contained in a 

 cyst. The cysts are numerous, white, oval in shape, of a gritty 

 nature, and between the 30th and 40th of an inch in length. 



The Entozoon he supposes to be the Trichina spiralis, heretofore 

 considered as peculiar to the human .species. He could perceive no 

 distinction between it and the specimens of T. spiralis which he had 

 met with in several human subjects in the di.ssecting-rooms, where 

 it has also been okserved bj' others, since the attention of the scien- 

 tific public has been directed to it by Mr. Hilton and Profes.sor 

 Owen. 



Dr. Leidy also exhibited a singular knotted mass of living Gordii 

 or hair worms, with numerous long strings of ova attached, which 

 had been taken a few days since from one of th*^ hydrants of this 

 city. 



[June. 1847. No. 17. See Bibliography.] 



Dr. Leidy exhibited a drawing of an Entozoon (a .species of Dis- 

 toma') found in the pericardium of Helix alternata. This Entozoon 

 is half a line in length by a quarter of a line in breadth, a large com- 

 parative size, when its .situation is considered, being equal to that 



