168 



^loup; the dorsal rib is composed of two, which are widely separated only towatds 

 their free ends. Spicula two; awl-shaped, bordered by a very narrow membrane; 

 the chitinous cylinder is apparently fenestrated. At either side of ihc genital orifice 

 are two knobbed papilhe. Female relatively stouter ; vulva jnst iu frout of auns, 

 which is midway between it and the acutely pointed tail, usually covered by a hard 

 brown patch ; reproductive organs in two symmetrical seta anteriorly directed, ex- 

 cept a small portion of one, which is at first posteriorly directed to form a loop in 

 frout of the anus. Uteri two, in the caudal end of the body. These may be traced 

 up to the oviduct and ovaries, which continue to the cephalic end of abdomen, where 

 they are reflected to form a loop and thence continue to the caudal end to foru) still 

 another loop. The ovary of the caudal uterus forms still another loop nearly oppo- 

 site the uteri. 



Eggs laid with gastrula inclosed; length, 0.09'""'; width, 0.05""". Embryos from 

 0.23""" upwards. The largest found iu tumors were 4""" long; the smallest male 

 found in intestine was 7""» long. The smallest embryos were without digestive ap- 

 paratus. The largest possessed an intestine, unicellular glands, and a well-formed 

 chitinous spherical cup in the head; also six cephalic papilhe, and at the neck two 

 papilhB and a well-defined fold. 



Occurrence. — The adults live ia the large intestine of sheep below the 

 caecum; the embryos live iu the intestinal walls in tumors, which, 

 though more abundant iu the cjBcum, may be scattered from the duode- 

 num to the anus. The species is distributed in the United States east 

 of the Mississippi River as far north as Maryland, perhaps farther north. 

 Ou comparing the species with others of the genns it was found that it 

 corresi)onded more nearly with (Esophagostoina venulosum, a parasite of 

 goats, than any other described iu modern works, and that it corre- 

 si)onded still more closely with 0. aautum, Molin. (// sottordine degli 

 acrofalli. Memorie dell * * * IsUtuto Vencto, 1860, Vol. IX, p.^ 

 449.) The latter is apparently a distinct species, although in quoting ^ 

 other authorities he has given an incorrect synonymy. 0. Goluinbia- 

 nuni differs markedly from 0. venulosum in not having an inflated uerA:, 

 and from the latter and 0. acutum by the possession of a lapel of skin 

 upon the ventral side of the neck, just in front of the opening of the uni- 

 celUilar neck glands. Molin examined two males and three females of 

 0. acutum from Antilope Bupicapra; one male from Capra Hircus, var. 

 Mambricus, iu association with forty-five Sclerostoma liypostomum ; and 

 two males and one female from Capra Amnion. The finding of Scleros- 

 toma liypostomum in association with tlie (Esophagostoma acutum is the 

 fact which leads me to infer that the latter occurred in the large intes- 

 tine of the above mammals and not in the stomach, as he cites iu his 

 synonymy of the species. 



Life history. — (Esophagostoma Golumhianum seems to have become a 

 ])arasite of sbeep since their introduction into this country'. If present 

 in the Old World at all it is sparingly so, and seems to have esca|)ed 

 detection. So little is known about its distribution, that it is impos- 

 sible at present to accurately define its limits. From its great abun- 

 dance in the Southeastern States one might infer that it had originated 

 as a sheep parasite iu that region, and probably from some animal of 

 allied organization and hal)its. Tiie writer is at present inclined to 



