vni. B. 6 Walker: (Esopliagostomum Apiostomuni: I 503 



species, names undetermined. The oesophagostomum found in- 

 fecting these monkeys has been compared with the descriptions, 

 and appears to be (Esophagostomum apiostomum Willach, the 

 species common in apes and, according to Leiper, found in man. 



Since the infections are usually not heavy and the immature 

 adults escape into the lumen of the intestine only at intervals, 

 mature females and free ova are difficult to find. Careful search 

 will, however, reveal a few ova from time to time in the faeces 

 or in the contents of the large intestine at necropsy. 



The ovum at the time of its passage in the fresh faeces is oval, 

 gray, thin shelled, and in an advanced stage of segmentation. 

 Earlier stages of segmentation can be found in eggs from the 

 intestine, especially the caecum. In general appearance the 

 ovum resembles closely that of Ankylostoma. The ovum of 

 (Esophagostomum is, however, larger than that of Ankylostoma, 

 Necator, or Strongyloides, all of which it somewhat resembles. 

 The ovum of (Esophagostomum measures from 0.044 to 0.057 

 millimeter in breadth by 0.073 to 0.084 millimeter in length. Its 

 general characters and its resemblance to the ovum of the hook- 

 worm are well illustrated in Plate I, fig. 1. 



That the ovum described from the faeces is that of oesopha- 

 gostomum was proved by comparison with the ova found in a 

 mature female worm. If pressure be exerted on such a worm 

 under the cover glass, the whole viscera is evacuated through 

 the oral orifice, the uteri filled with ova remaining intact. Com- 

 parison and measurements of such nearly mature ova intra 

 uterum, show that they are identical with the ova found in the 

 faeces and described as those of oesophagostomum. Moreover, 

 none of the monkeys contained intestinal worms, the ova of 

 which could be mistaken for those of oesophagostomum. 



Development of the ova of oesophagostomum takes place 

 readily in cultures made in the same manner as for the develop- 

 ment of the ova of the hookworm. Powdered charcoal is added 

 to the faeces and, if necessary, a little sterile water, and the 

 whole is thoroughly mixed and spread in a thin layer in a sterile 

 Petri dish. The development takes place less readily, but to 

 some extent, in the undiluted faeces. 



The ova hatch in such cultures in from twelve to twenty-four 

 hours, nearly all that will develop doing so by the end of the 

 first day. The ovum gives rise to a rhabditiform larva measur- 

 ing about 0.34 millimeter in length by 0.016 millimeter in breadth. 

 This larva (Plate I, fig. 2) possesses certain peculiarities which 

 plainly distinguish it from the rhabditiform larvae of the hook- 



