34 A FLORA WITHIN ANIMALS. II. 



1. Arthromitus eristatus, LEIDY. 



Proc. Acad. Nat. Sci., iv., 227. 

 Arthromilus nitidus, Leidy : ibid., v., 35. 



(PiATE II., Fig. 1, i; V. 3, d, 14, 15 ; VI. 5 e; VIII. lf,2d, 3, 4, 5.) 



Tliallus very delicate, filamentous, linear, straight or inflected, flexible, colorless, 

 translucent, obtusely rounded at the free end. Pedicle of attachment one or more 

 atnber-colored round or oval granules. Articuli indistinct, but becoming well- 

 marked after the development of the interior sporular body. Spore oval, simple, 

 faintly yellowish, translucent, highly refractive, usually lying oblique and alter- 

 nating in position in different articuli. Length from the y-^Tr to the ^ of an inch. 

 Breadth about the -j^-l-g-g- of an inch. 



Habitation. Parasitic, grows from the mucous membrane of the ventriculus and 

 large intestine of Julus marginatits, and also upon Enterobryus elegans, Ascaris in- 

 fecta, Streptostomum agile, and T/ielastomum attenuatum ; from the mucous membrane 

 and its appendages of the ventriculus of Passalus cornutus, and Polydesmus virgini- 

 ensis, and upon Eccrina longa. 



8. HISTORY, STRUCTURE, ETC. OF ARTHROMITUS. 



The genus Arthromitus, I first detected growing within the ventriculus of Julus 

 marginalus. Some time subsequently, I detected much larger filaments of the same 

 plant, with relatively very distinct articuli, growing within the large intestine of 

 the same animal, which I supposed to be a distinct species from the former, and, 

 therefore, described it as such under the name of Arthromitus nitidus. Since then, 

 within Julus marginatus, Passalus cornutus, and Polydesmus virginiemis, I have ob- 

 served Arthromitus under a variety of conditions, and in all gradations of size and 

 development, from the simple, exceedingly minute, inarticulate filament, to a length 

 of one line, with distinct articuli ; and therefore I cannot, at present, distinguish 

 more than one species ; and for this, the name is retained which was first proposed. 



As just stated, I have observed this entophyte from the condition of an exceed- 

 ingly minute, delicate, inarticulate filament to a thallus one line long, and dis- 

 tinctly articulate, and containing within very many of the articuli, sporular bodies. 



Frequently, there may be detected, growing with the undoubted thallus of Ar- 

 thromitus, filaments of the former character ; simple, hyaline, and inarticulate, as 

 short as the -5-^-$ of an inch, as long as the -^ of an inch, and not more than the 

 sr&TFTT f an i ncn in diameter. With these are intermingled filaments, very faintly 

 articulated, measuring up to the y^-J^nr of an inch in diameter. 



Within the ventriculus of Julus marginatus, this entophyte, when fully deve- 

 loped, measures from the ^ 7 to the %%-$ of an inch in length, by the ^T^T to the 

 islinr f an inch in diameter. 



Within the large intestine of the same animal, Arthrotnitus appears to reach its 



