130 RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 



composed of carbonate of lime, as they are dissolved by acetic acid 

 with au abundant evolution of carbonic acid. 



From the form of the head the worm was named Dibothriiun 

 cor dice ps. 



Numerous leeches collected b}' Prof. Hayden's assistants, Messrs. 

 Carrington and Dawes, in a lake in Wyoming Territory, appear to 

 belong to the species Aulastoviuni lacustris, first discovered several 

 years ago in Twin Lake, Minnesota (Proc. Acad. Nat. Sci., 1868, 

 p. 229). Mr. Carrington informs us that the head of a horse, which 

 was thrown into the lake, in a few hours appeared black from the 

 quantity of these leeches which adhered to it. It is barely probable 

 that this leech is the one described by Thomas Say, in Long's Expe- 

 ditions, under the name of Hirudo marmoraia, though the characters 

 do not accord with his description of the latter. It is not improb- 

 able that the two are quite distinct. H. niamiorata, together with 

 another species, H. lafej-a/is, was obtained from small lakes on the 

 high land between Lake Superior and Rainy Lake. Neither of 

 these appears to have been obtained since their first discovery. 



Several large hair worms from Fish Creek, Montana, pertain to 

 the species (iordius lacustris, previously described from specimens 

 obtained in Kansas. It is the largest known Gordius. The females 

 of the Kansas specimens range from 10 inches to 2}'^ feet in length, 

 the males from 8 inches to upwards of 2 feet. The females of the 

 Montana specimens measure from i^ to 2]^ feet in length, a male 

 8}^ inches in length. The females are pale brown, the males dark 

 brown and with a strongly forked tail. 



[January, 1872. No. 365. See Bibliography.] 



On a Mite in the Ear of the Ox. — Prof. Leidy remarked that he 

 had received a letter from Dr. Charles S. Turnbull, in which he 

 stated that while studying the anatoni}- of the ear he had discovered 

 in several heads of steers, at the bottom of the external auditory 

 meatus, a number of small living parasites. They were found at- 

 tached to the surface of the membrana tympani. Specimens of the 

 parasite preserved in glycerine, and a petrosal bone, to which several 

 of the parasites were clinging, were also sent for examination. These 

 proved to be a mite or acarus, apparently of the genus Ganiasiis. 

 The body is ovoid, translucent white, about 3-5ths of a line long 

 and 2-5ths of a line wide. The limbs, jaws, and their appendages 

 are brown and bristled. The body is smooth or devoid of bristles. 

 The limbs are from 2-5ths to Vz a line long. The feet are terminated 



