1876.] DR. T. S. COiJEOLD ON ENTOZOA. 203 



label on the jar was in places well nigh obliterated, I made out that 

 the worms had come from a Monkey ; but not being certain as to the 

 species, I did not attempt the identification of the parasites. . Dr. 

 Murie has since further obliged me by looking up his notes ; and on 

 the 2nd of April 1875, he informed me by letter that the host was a 

 Pinche Monkey {Ha pale cedipus). This well known Marmoset had 

 been obtained from New Granada. The cause of the animal's death, 

 which occurred at the Society's Gardens on or about the 30th of June, 

 1866, was not ascertained. I have not in this case observed any signs 

 of inflammation in the intestine of the host, a portion of which, with 

 several of the Entozoa remaining attached was also supplied to me. 

 The mucous layer of the gut shows deep conical depressions at 

 the spots where the detached worms had anchored themselves. 



So far as I can make out, Diesing's original description of the 

 parasite is the only one that exists. I have gone over his numerous 

 memoirs contributed to the Vienna Accademy, but can find nothing 

 beyond the specific characters given in his * Systema. ' All the 

 specimens in the Vienna Museum, whence his description is taken, 

 were collected by Natterer. They were procured from the Marakina 

 (Midas rosa/ia), from two other true Marmosets {Hapale ursulus 

 and H. chrysoleucus), and from a Squirrel Monkey or Tee-tee 

 ( Callithrix sciureus) . 



Though in one or two unimportant particulars our observations 

 do not agree, Diesing's description is amply sufficient for the sys- 

 tematist's purpose. By referring to the four specimens which I 

 have selected for illustration, it will be seen that all the worms 

 were more or less bent upon themselves. The larger specimens 

 present a tolerably uniform thickness throughout, the smaller ones 

 being thicker behind and almost club-shaped (Plate XVI. fig. 1). In 

 detached examples, the front end of the parasite is seen to support a 

 narrow and long neck, which is usually well marked off from the 

 body proper (77). It is more or less regularly annulated, the folds 

 being continued downwards along the body, but gradually losing 

 their regular arrangement. If the anterior extremity of the neck be 

 examined with a powerful pocket lens, its abrupt and truncate sur- 

 face will be seen to display a number of lines or grooves radiating 

 from a common centre (fig. 2). During the perfect retraction of 

 the proboscis the centre is represented by a clear space, or wide 

 opening, which communicates with a cavity immediately beneath. 

 The end of the neck thus forms a sort of collar, or rosette, made up 

 of rays arranged like the spokes of a wheel. When the proboscis 

 is exserted this collar is more or less convex, but it becomes slightly 

 concave when the proboscis is retracted. Not improbably this at- 

 tractive-looking surface suggested to Diesing the specific title which 

 he gave to the worm. He recognized 24 rays : they probably vary 

 from that number up to 28 ; at least, I counted 27 in the specimen 

 (fig. 3). During exsertion, the proboscis forms, to the naked eye, a 

 nipple-like projection (fig. 2). According to Diesing it supports 

 three rows of hooks ; but I certainly saw four rows (fig. 4). When 

 separately magnified these hooks present very different appearances 



