NATURAL SCIENCES OF PHILADELPHIA. 69 



limited regions in England in the course of fifteen months. In Beeking tor 

 the source of the small thread-worm, or Ozyuris vermicularis, which infi 

 man, I have also been led to discover some new species, of which I pro] 

 in due time to publish descriptions with drawings. As is commonly the 

 in organic nature, we find the specific form changing with the cbang< in 

 condition, but the species are often fouud to differ where difference in the con- 

 ditions are hardly appreciable. 



Mr. Bastian, in a note to his description of the Vinegar-eel, Anguillula aceti, 

 says he was indebted to Dr. Davaine for the. opportunity of examining the 

 animals, and adds that "they are much less frequent than is generally 

 imagined, at all events in England ; and this may be due in gnat measure to 

 the adulteration of our vinegar with sulphuric acid." It would thus appear 

 that the Anguillula aceti he examined was contained in a specimen of what 

 may be suspected to have been the wine vinegar of France. The cider vinegar 

 so commonly used in this country usually teems with Vinegar-eels. Our 

 cruets, when held up to the light, even to the sharp sight of a naked eye fre- 

 quently exhibit the worms swarming, especially 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 Anguillula aceti, which 

 1 infer to be the wine Vinegar-eel, it appears to belong to a different specieB. 

 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 ani- 

 mal, proposing to do so in 'future, together with other species. I may say, 

 however, while it has nearly the size and form of the Anguillula uceti, it has the 

 oesophagus of the form in the genus Cephalobm of Bastian. 



June 21st. 

 Wm. S. Vaux, Vice-President, in the Chair. 



Twenty members present. 



Prof. Leidy remarked that the two fossils presented this evening by Dr. W. 

 F. McAllister, of Burlington, Kansas, were obtained in that vicinity from 

 gravel, at a depth of thirty feet, in digging a well. One of the specimens con- 

 sists of a plate from a large molar of the American Elephant, Elephas Ameri- 

 canus. The other is the fore part of a ramus of a lower jaw of an Ox, perhaps 

 of a large individual of the Bison Antericanus. In comparison with the corres- 

 ponding part of the jaw of the existing animal, the measurements are as 

 follow : 



Fossil. Recent jaw. 



Depth at fore part of first molar 24 lines. 21 lines. 



Depth at incisive foramen. 26 " 24 



Depth at lowest part of hiatus 21 " 18 



Length of hiatus in advance of molar 52 52 



Thickness below first molar 14 " H 



Prof. Leidy further stated that he had recently received for examination a 

 small collection of fossils, through the Xew York Lyceum of Natural History 

 and the aid of his friend Mr. George X. Lawrence, which belonged to Mr. Win. 

 Newcomb, of New York. The collection is said to have been brought from 

 the Rocky Mountains, but the exact locality has not yet been ascertained. 

 Most of the fossils consist of fresh-water shells, evidently of tertiary age, but 

 adherent matrix indicates them to have been derived from several different 

 strata Accompanying them there are a few bones, of which one is the coro- 

 nary bone, apparently of Equus excelsus ; the others mostly pertain to 

 fishes a large cvprino'id and a ray. As the living cyprinoids are fresh-vi 

 fishes the association of the remains of a ray may perhaps indicate that this 

 was also a fresh-water species, though it is not unlikely that it may belong to 



1870.] 



