II. A FLORA WITHIN ANIMALS. . 31 



they are generally granular, often to the exclusion of globules, and are divided into 

 distinct masses in tlie course of development into secondary cells. 



In Eccrina loiifja, the secondary cells in their origin are lirst observable as relative!}' 

 short cylindrical divisions of the cell-contents within the distal extremity of the 

 principal cell (-3). Their number does not always correspond with the length of 

 tlie thallus. Thus, I have observed filaments ol lines long, with 25 secondary cells; 

 others of G lines, with from 12 to 20 ; some of 7 lines, with from 16 to 30, etc. 

 Nor is the length of the secondary cells uniform, nor in relation with that of the 

 thallus (1-4). They vary in the same and in different individuals in this re- 

 spect. In some individuals they are found increasing in length successively from 

 the first to the last, indicating a continuance of growth during the process of 

 development by division from the primary cell. Tluis, in an individual of 6 lines 

 in length, with 24 secondary cells, the first measured the gl^ of an inch in length, 

 by the ^^-^ of an inch in breadth, and the othei's very gradually increased in length, 

 but diminished sliglitly in breadth to the last, which measured 3 J-^ of an inch in 

 length by the jjj^ of an inch in breadth. In another individual, 5 lines in length 

 with 12 secondary cells, these were nearly uniform, measuring from -^^-^ to 3^-^ of 

 an inch in length by yi^ of an inch in breadth. In another, of 4 J lines with 16 cells, 

 they all measured y^-g- of an inch in length by g^y of an inch in diameter. In 

 another, of 7 lines with 25 secondary cells, the first measui-ed ^ J|j of an inch in 

 length, the fourth only ^l^ of an inch, and the last gj-g- of an inch. 



The contents of the secondary cells, from their earliest condition, are uniformly 

 granular (l,c; 2, b; o, h; 4, a), and in mass appear white and opaque. The granules 

 are distinct, spherical, transparent, and colorless, and measure from 15I00 to 

 ysVo' of ^^^ i"ch in diameter. I never observed globules within the attached 

 secondary cells, but have seen them within those which have become detached, 

 which will be again referred to (G,a). ■ 



The contents of the primary and secondary cells and the cell-wall, conduct them- 

 selves, upon the application of chemical reagents, in the same manner as Enterohrijus. 



In the progressive formation of secondary cells, the first step is the division of 

 the contents within the distal extremity of the primary cell into separate cylin- 

 drical masses. 



At the circumference of tlie planes of division, a constriction of the primordial 

 utricle is very early observable, and sometimes a constriction of the permanent 

 cell-wall rapidly follows or is almost coexistent, but frequently it does not form 

 until a late period, as in Enterobryus elegaiis. 



Upon the segmentation of the contents within the distal extremity of the primary 

 cell in the formation of secondary cells, the inner surface of the permanent cell- wall 

 appears to become combined or continuous with an extremely thin and delicate 

 membranous layer occupying the planes of separation of the cylindrical, granular 

 cell-masses, which I suspect is derived from the primordial utricle, or preferably 

 from the coagulation of a portion of protoplasma, which has exosmosed from the 

 interior of the cell-masses, each inclosed within a distinct sac of the primordial 

 utricle, into the interspace at their extremities. This, I say, I suspect to be the 

 mode of origin of the partition continuous with the permanent cell-wall between 



