100 [September, 1846. 



Meeting for Business, Sept 29, 1846, 

 Vice President Morton in the Chair. 



The committee on Dr. Leidy's paper, on a new genus and 

 species of Entozoa, reported in favor of publication. 



Description of a new genus and species of Entozoa. 

 By Joseph Leidy, M. D. 



In the course of an investigation of the anatomical structure of 

 the terrestrial gasteropoda of the United States, I discovered a 

 microscopic entozoon inhabiting the fluid contained in the vessie 

 copulatrice or spermatheca of Helix albolabris, since which I have 

 found it to exist in two other species, Helix tridentata, and Helix 

 alternata, and I have no doubt of its existence in others, not yet 

 having had an opportunity of examining further. As there ap- 

 pears to be no known genus in which this animal can be placed, 

 I have been necessitated to form the following : 



Cryptobia. Animal minute ; form exceedingly proteoid ; inter- 

 nal organization cellular or granular. 



C. helicis. Colorless; form, ordinarily elongate, ellip- 

 solid, fusiform, or ovate; caudated, caudse opposite, one longer 

 than the other. Internal granular structure consisting of two 

 large cells and numerous minute granules. Total length from 

 the 126th to the 100th of a line. Habitat, the vessie copulatrice 

 or spermatheca of Helix albolabris, Helix [tridentata and Helix 

 alternata. 



The name of this genus is derived from x/wrd?, hidden and 

 PiSat } to live. This singular entozoon in its general appearance 

 and organization appears to be intermediate between Cercaria 

 seminis and Filaria. Its varied form and movements are curious 

 to observe ; at one moment globular, then oval, ovate, fusiform, sig- 

 moid, crescentic, &c, it appears as if it would outvie the kalei- 

 doscope in its changes. The motions are vibratile, rotary, with 

 a lateral progression, or whirling in circles like the insect Gyrinus. 



Cryptobia helicis might be confounded with the spermatozoa 

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

 which they are found being connected with the generative appara- 

 tus, and its supposed use as a spermatheca, but they may be readily 



