[13] ON MERMIS ACUMINATA. 125 



Filar ia Mendinensis owe its introduction into the human body 

 from the custom which prevails in those countries where the 

 worm is found, of using insect food. Insects are well known 

 to be infested with Filarise, probably more than any other 

 class of animals. In Egypt, Arabia, etc., the locust is eaten ; 

 in Guinea, etc., the larger coleoptera, in the raw state; and in 

 this condition Filariso may often be swallowed, and reach a 

 higher development of their existence in the human body. 



In the same paper, Dr. Leidy describes two additional spe 

 cies of similar Entozoa, the one (Filaria canis cordis) as 

 indicated by the name given it, taken from the heart of a dog. 

 The two examples were white, opaque, linear, nearly uniform 

 throughout, posteriorly subulate, pointed ; mouth simple, 

 round. Length ten to ten and a half inches ; greatest breadth 

 f of a line, anteriorly ^ of a line. The other species (Filaria 

 boce constrictor is), was found in the areolar tissue, in an 

 irregular or tortuous position, between the muscles of the ribs 

 and the integument of a boa constrictor. This was a more 

 robust form, ten inches in length by f of a line broad, of a 

 white color and longitudinally striated. 



Dr. Leidy has also recently found* the common house-fly 

 (Musca domestica, it may be presumed) to be infested with a 

 thread-worm, of about a line in length, which takes up its 

 abode in the proboscis of the fly. From one to three worms 

 occurred in about one fly in five. The parasite was first dis 

 covered in the house-fly in India, by Carter, who described it 

 as Filaria muscce, and suggested that it might.be the source 

 of the Guinea-worm in man. 



In view of these unwelcome suggestions, that it may be a 

 necessary section of the life history of several of these entozoa 

 that they should be introduced into the human body through 

 the food of which we partake, there to undergo their final devel 

 opment, it is much to be regretted that the entire history of all 

 the species to which man is exposed is not yet known. Much 

 attention has been paid to them, but their study has proved 

 a difficult one. A monograph of the Hair-worms, by M. 

 Yillet, has recently been published, of which we know nothing 

 beyond .the information given in the American Naturalist for 

 December, 1874, to the effect that it was then being published 

 in the - Archives de Zoologie Experimentale.&quot; The author had 

 found the larvae encysted in the larvae of CHIRON OM us (be- 



* American* Naturalist, Vol. IX, p. 247. 1875. 



