32 A FLORA WITHIN ANIMALS. H. 



the secondary cells ; for when the cell-masses, at an early period of their division, 

 are made to shrink from one another by the application of acetic acid, an exceed- 

 ingly delicate, but entire membranous partition is observable, or none at all ; and in 

 no instance could I detect a concentric growth from the inner surface of the per- 

 manent cell-wall ultimately intended to separate the cell-masses. After the forma- 

 tion of the membranous partition described, the permanent cell-wall at the boundary 

 of the former becomes constricted, and the secondary cells are apparently completed 

 by a splitting of the membranous partition through the advancing constriction of 

 the permanent cell-wall. 



Before complete division of the secondary cells, the permanent cell-wall at the 

 margin of its constriction above and below, is somewhat thickened (2 c), but after- 

 wards again assumes the general thickness, and the two portions of the divided 

 partition between the secondary cells are thickened to the extent of the lateral 

 portion of the cell-wall. Frequently, the secondary cells become detached before 

 the cell-wall at the end has become as thick as it exists laterally, and in such 

 cases the circumference of the extremity is indicated by a thickened annulus of 

 the cell-membrane, while that portion of the latter included within the area of the 

 annulus, resembles the crystal upon the face of a watch (4, a) ; an appearance, as 

 before stated, frequently observed at the free extremity of the primary cell of 

 Enterobryus attenuatus, and of Enterobryus elegaiis. 



The course of development of the secondary cells of Eccrina moniliformis is the 

 same exactly as that of Eccrina longa. It is, however, more striking, from the 

 extraordinary number of cells involved in the process, which exhibit a very gradual 

 progression from the earliest stage to the fully-developed cells. In this species the 

 early divisions of the cell-contents within the distal extremity of the primary cell 

 are transversely oblong, but soon assume the globular form as they successively 

 approach the free end of the thallus. 



The secondary cells of Eccrina, in all their stages, uniformly possess granular 

 contents. 



2. Of the Pedicle of Eccrina. — This has the same structure and mode of attach- 

 ment as in Enterobryus, but it is always relatively very short. 



3. Of the Position of Growth. — I have found Eccrina growing only from the 

 mucous membrane of the ventriculus of Polydesmus virginiensis and Polydesmus 

 granidatus, especially at its commencement, in which position it reaches its most 

 perfect development. I never detected Eccrina longa growing upon Thelastomwn 

 labiatum, an entozoon of Polydesmus virginiensis. 



4. Of the Development. — As in the case oi Enterobryus, I have never been able to 

 observe the process from the spore, but have traced it from a very early condition, 

 most probably derived from the latter, and also from the secondary cells detached 

 from the parent plant. 



Detached secondary cells of Eccrina longa, are not unfrequently observed in- 

 termingled with the growing filaments of the mother plants. The form of these 

 detached cells is like those at the free end of the row of secondary cells still attached 

 but ripe for separation, that is, oblong, or short cylindrical, with obtusely rounded 

 extremities. They are filled with uniform granular contents, as in the attached 



