RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 1 25 



In seekino: for the source of the small thread-worm, or (Xvjnais ver- 

 micidaris, which infests man, I have also been led to discover some 

 new species, of which I propose in due time to publish descriptions 

 with drawings. As is commonly the case in organic nature, we find 

 the specific form changing with the change in condition, but the 

 species are often found to differ w'here differences in the conditions 

 are hardly appreciable. 



Mr. Bastian, in a note to his description of the Vinegar-eel, A)i- 

 guillida aceti, says he was indebted to Dr. Davaine for the opportunity 

 of examining the animals, and adds that " they are much less fre- 

 quent than is generally imagined — at all events in England ; and 

 this may be due in great measure to the adulteration of our vinegar 

 with sulphuric acid." It would thus appear that the Aiiguillula 

 accti he examined was contained in a specimen of what may be sus- 

 pected to have been the wane vinegar of France. The cider vinegar 

 so commonly used in this country usuall}' teems with vinegar eels. 

 Our vinegar cruets, when held up to the light, even to the sharp 

 sight of a naked eye, frequently exhibit the worms swarming, espe- 

 cially at the border of the surface, as if in search of both air and light. 

 By comparison of our cider Vinegar-eel with Mr. Bastian's description 

 and drawings of the true Aiigjiillula aceti, which I infer to be the 

 wine Vinegar-eel, it appears to belong to a different species. From 

 the descriptions of previous authors of the European Vinegar-eel, I 

 had considered ours as the same. I shall not now give a description 

 of the animal, proposing to do so in the future, together with other 

 species. I may say, however, while it has nearly the size and form 

 of the Anguilhda aceti, it has the oesophagus of the form in the 

 genus Cephahbus of Bastian. 



[August, 1870. No. 331. See Bibliography.] 



Prof. Leidy exhibited in a vessel of water numerous living speci- 

 mens of a leech, which he said was abundant in the vicinity of Phil- 

 aielphia, but appears to be an undcscribed .species. He had first 

 observed it in a pond on the Delaware, near Beverly, Burlington 

 county, X. J., from which he obtained the large.st .specimens. It 

 was found especially beneath half- submerged dead limbs of trees, 

 sometimes between the bark and the wood, and in crevices and holes 

 of the latter made by in.sects. It was also found in the Delaware 

 and Schuylkill rivers near shore, beneath stones. In ditches 

 below the city, and communicating with the rivers mentioned, 

 smaller leeches, apparently the young of the same, were frequently 

 between the leave sheaths of submerged stems of aquatic plants, 



