28 A FLORA WITHIN ANIMALS. XL 



form of Enterohnjus. The plant is fixed upon the mucous membrane of the in- 

 testinal canal, in which it grows, and from its delicate structure it must be more or 

 less constantly liable to rupture in the peristaltic movements of the bowels, and 

 the passage onwards of the food; but from the spiral arrangement of the thallus 

 of Enterohryus elegans and Enterohryus spiralis, and the sigmoid flexure of that of 

 E liter ohry lis attenuatus, the graceful filiform plants may be elongated or stretched 

 onwards for a considerable distance without danger of being torn. (See PI. I.) 



6. Reproduction of Enterohryus. — It is no doubt the case that Enterohryus is not 

 only reproduced by segmentation, but also by spores, although in several thousand 

 individuals of Enterohryus elegans which I have examined, in over one hundred 

 and fifty individuals of Julus marginatus, from early spring until late in the 

 autumn, I am not positively certain that I either observed the formation of the 

 spores, or the development of the plant from the spore. 



The earliest condition in which I have been able to detect Enterohryus elegans, 

 was in the form of a delicate, transparent, colorless, globular, oval, or ovate vesi- 

 cle, measuring the 2^5^-0 of ^^ i^^ch in diameter, or almost the -^^^-^ of an inch long, 

 by the j-g-^-g of an inch broad (PI. IV. 3). The contents consisted of a colorless 

 protoplasm. When elongated, the poles of the parietes were thickened, and one 

 end was adlierent to the mucous membrane of the viscus in Avhich these bodies 

 were found. 



In the next stage, the young Enterohryus had the form of a delicate, colorless, 

 oblong, oval cell, the xoVt of f-n inch long by the 2^-o of an inch broad, filled 

 entirely with a faintly granular substance; or in other instances, with a mixture 

 of this and glolDules, or with globules alone, attached by one extremity to a slight 

 conoidal, pedicular elevation, arising from the surface of support (4-6). From 

 this period, as it advances in its development, it is usually disposed to grow in a 

 cylindroid, curved, clavate form, in which state it may be frequently met with 

 from the size above given to the y|-g- of an inch in length (8, 10). Having 

 reached the latter point, it becomes more cylindrical, and up to the ^V of an inch 

 in length is disposed to grow into a single spiral coil (11). 



Generally the cell-contents, from the earliest condition above mentioned, be- 

 come almost wholly globular; but within the rectum of Julus marginatus, the 

 contents of the plant-cells retain their granular appearance, occasionally with a 

 very few globules, until the latest period in which I have observed them. 



Occasionally, the young thallus of Enterohryus elegans grows to y\ of .an inch in 

 length, perfectly straight, cylindro-clavate in form, and filled with globules 

 (13, 14). Less frequently, it is found constricted somewhere near the middle of 

 its length, the distal portion broader than the attached (15). More frequently 

 than in the two last cases, it is found having a sort of geniculate bending at an 

 obtuse angle in some part of its course, usually below the middle, but occasionally 

 above it, with the distal portion possessing a greater diameter than the lower por- 

 tion, which is straight, while the former is often curved, occasionally recurved 

 though sometimes also straight (17). 



The young of Enterohryus attenuatus I observed growing within the ventriculus 

 of the larva of Passalus cornutus, from the ^^-^ of an inch to the yig of an inch in 



