570 DR. J. B. HICKS ON THE GONIDIA AND 



The observations of Dr. Caspary*, whicli show that Chroolepm produces zoospores, 

 are not inimical to this view, as will be pointed out in the course of the following 

 remarks. In addition I may also add that I have often observed the peculiar form 

 of the end-cells giving off these zoospores, as figured by him in the older confervoid 

 filaments of Mosses. 



The gonidia mentioned by Kiitzing (in the characters of Protonema) as being thrown 

 off from the filament were fii-st noticed by him f, who also showed that they sprouted 

 out again into a filament, but that whilst free they were globular and then looked like 

 Protococciis-cells. 



Beyond this point in their history, and the knowledge of their "peculiar fruit" {tn- 

 bercles, Schimper) and the propagules of SchimjDer, I am not aware that any one has 

 preceded me in the observations about to follow. Before proceeding further, it will be 

 useful to describe more particularly the "confervoid filaments." 



They consist of a single series of cells, of a length varying according to outward con- 

 ditions, each cell possessing the property of forming branches like themselves. They 

 are, in the first instance, produced by the germination of a spore, as has been pointed 

 out by the observers above quoted ; and although, as Schimper % has beautifully shown, 

 the ascending axis arises from them, yet the axis and the leaves in their turn give 

 rise to the filaments, as Ktitzing § and Schimper also have pointed out, and which can 

 be readily verified. 



When the filament springs from either axis or leaf, or from a single unsegmented goni- 

 dium, the first change in the ceU (for in either case only one cell is involved) is a bulging 

 out of a portion of its wall, which, after growing a certain length, is shut off from the 

 original ceU by a septvim at the point of origin || (PL LVII. fig. 2). After this cell has 

 grown a certain length, a binary subdivision of its contents takes place, upon the plan 

 common to that form of parietal cell-formation ^. 



* Quart. Journ. Mic. Sc. vol. viii. p. 159. t Linnsea, Band viii. p. 3fi0. 



X op. cit. supra. § Phycologia Generalis, Protonema. 



II This corresponds with Nageli's description of cell-formation in the Confervas (Ray Soc. 1845, p. 260) : — "The 

 cell-formation occurs in a similar manner when a cell grows out sideways from the stem to produce a branch. The 

 septum is then produced between the newly outgrown and the original portions of the cell. The cell-contents also 

 remain unaltered here while the septum is becoming apparent." Again (Ray Soc. 1849, p. 141), "A cell 

 grows out into a branch, and divides by parietal cell-formation into two cells, in such a way that one corresponds to 

 the original cavity of the cell, the other to the expanded part. Here are to be enumerated the tbrmation of 

 branches in Algse, Fungi, Floridese, &c. It probably exists in all plants, but may be recognized best in organs com- 

 posed of rows of cells." 



^ " The mode in which the process of division of cells takes place has been represented in different ways. While 

 Unger explains the division of the cell- contents by the production of a dissepiment (partition), Nageli, comprehending 

 more correctly the relations of dependence between the formation of membrane and the contents, states, vice versd, 

 that the formation of the septum proceeds from the contents, previously divided into two halves ; and Hoffmeister, 

 in addition, directs attention here more particularly to the primordial utricle, bounding and cutting off the two parts 

 from each other, even before the origin of the cellulose dissepiment. According to this representation, the septum is 

 formed by the two individualized portions of contents into which the mother cell divides, and which secrete cellulose 

 upon their whole surface after they become separately constituted, touching by their flat adjacent surfaces, whence, of 

 course, the cellulose layers formed on the surfaces in contact become united and thus form what appears a single 

 septum, which, however, from the nature of its origin, is composed of two plates. Referring to the ab origine 

 existing contact of the daughter cells with the whole internal surface of the wall of the mother cell in the formation of 



