36 A FLORA WITHIN ANIMALS. IL 



3. Of the Mode of Attachment of the Thallus. — Although the attachment of 

 Arthromitus is very firm and tenacious, yet the thallus possesses no pedicle like 

 that of Enterobryus and Eccrina, but grows from granular bodies resembling those 

 upon -which the algoid filaments of the human teeth, and those of other animals, 

 arc based. 



The granules of attachment, from which a few filaments start, are often single 

 or isolated ; but usually there is an aggregation of several granules, from which 

 grow more or less dense bunches of the plant (3, e; 14, a; VIII. 5). The granules 

 adhere to their basis of attachment as if cemented. They measure from the g-oo o o 

 to the 16^0 of ^^ iiich in diameter; usually appear globular in form, and are 

 amorphous and amber-colored, and refract light as highly as oil-globules. 



4. Of the Particular Locality and Mode of Qrowth.-^ Arthromitus may be found 

 in at least 90 per cent, of cases, within the ventriculus of Julus marginatus, rang- 

 ing from single isolated filaments to very dense bunches. It grows, in company 

 with Entei-ohyriis elegans, from the mucous membrane, especially near the com- 

 mencement of the organ. When in bunches, or tufts, the filaments spread or radiate 

 from their central granules of attachment, like a dense tassel held upwards. Oc- 

 casionally, the bunches ai'e found closely twisted, with their filaments intertwined 

 and plaited, forming columns, from the -g-oV o' ^^ ^^^ i^Vu of an inch in diameter, 

 spreading at the summit. 



Arthrom itus is frequently found growing upon Ascaris infecta, Streptostomum agile, 

 and Thehastomum attenuatum, upon any part of the exterior surface, but.mogt usually 

 from the lips of the anal and generative apertures, or the interspaces of the annuli 

 of the body; these, apparently, being the most favorable resting-places for the 

 sporuli from which the filaments are developed. 



It is also frequently found growing in great profusion upon Enterobryus elegans, 

 often in dense bunches, covering its summit (PI. III. 12), or in a number of con- 

 centric circles on any part of its length, or radiating from particular points (PI. YI. 

 1, A). A favorite locality for its growth, upon this species of Enterobryus, is the 

 basis of attachment of the pedicle of the latter, or the junction of this with the 

 primary cell. The youngest individuals of Enterobryus are sometimes so com- 

 pletely covered with Arthromitus as to be entirely obscured or hidden from view 

 (PL IV. 16, c). 



As before mentioned, Arthromitus reaches its highest degree of development in 

 the large intestine of Julus marginatus ; a curious fact, when we recollect that 

 Enterobryus elegans, although growing here iil greater profusion than in the ventri- 

 culus, never advances to the formation of secondary cells. In the same relation 

 to quantity as we find Enterobryus, with its state of development in the two cavities 

 mentioned, so we also find that Arthromitus, with its greater degree of perfection 

 in the large intestine, does not grow in dense bunches, as in the ventriculus, but in 

 a very small number of filaments associated together, frequently in pairs ; two, 

 four, or eight, often single, very rarely more than eight together. 



I have never observed Arthromitus to be parasitic upon the entozoa or Enterobryus, 

 within the large intestine of Julus marginatus. Arthromitus is found within the 

 ventriculus of Polydesmus vvrginiensis, but not in the profusion in which it occurs in 



