1 



r ■ 



THE GENUS CHLOEOCHYTRIUM. 



15 



Accoi'dino; to Rosenvlno-e's fitrures and 



material he found a number of individuals of approximately tlie same form 

 as that shown in Kosonvino-e's fioures. No zoospores were observed in this 

 species, hence liosenvingo's statement that there is no conical jiaj-illa on the 

 cells in the vegetative state is of no specific importance^ since Kjellman 

 describes the formation of the papilla as a preliminary step in the formation 

 and extrusion of the zoospores. The occurrence of the much thickened wall 

 in Freeman's form seems to bo a variation due to position , and must tlierefore 

 be disregarded in the separation of species, 



description the chloroplast is 

 parietalj but does not extend over the whole surface of the cell ; it may contain 

 one or two pyrenoids, or they may be indistinct. This again is an Insuf- 

 ficient basis for specific di^^tinction, since Moore "^ has definitely shown that 

 in (/. AJoorei^ N. L. Gardner, the extent of the chloroplast diflers accordino- 

 to the degree of development of tlie cell ; Freeman suggests that the limited 

 extent of the chloroplast may be due to the superficial position of the cell. 

 Chloiiochytrium inclusum var. dermatocolax (Reinke), nob, (188y), is 



much smaller than the typical form of C, inclusum^ Kjellm., and is found in 

 the superficial cell-walls of Polysiplionia elougata imd Sphacelarla raremosa f. 

 A form exactly resembling Reinke^s, but wdth rather larger cells w^as 

 recorded by Rosenvinge J from Sphacelaria and Chcetoptcris, hnt^ im^oviw, 

 natelvj neither Reinke nor Rosenvinge has figured the aKa he described. 



The cells are elongated and somewhat flattened, with a fairly thin cell-walk 

 The chloroplast forms a continuous parietal layer^ with ridges projecting 

 towards the inside of the cell ; later the cell-contents become cross- o^rained 

 and indistinct. In the absence of a figure the extent of these internal 

 projections of the chloroplast is unknown^ but if, as seems likely from the 

 description, they do not reach to the centre of the cell, then the chloroplast is 



Fre 



eman in 



seen to be only a further development of that observed 

 CAnelusum Kjellm., and there is no need for a separation of tlie two species 

 on this basis. It is just possible^ however, that the chloroplast may be of 

 the type described for (7- Lemnce and C. imradoicum^ and consequenth' it is 

 perhaps better to regard the alga as a variety of C, inclumm under the name 

 6\ inclusum^ Kjellm., var. dermatocolax (Reinke), nob., especially in view of 

 its comparatively small size. The formation of zoogonidia takes place in 

 exactly the same way as was described by Kjellman for C. inclusum. The 

 zoogonidia bore their w^ay to the inside of the host-wall again^ and the hoi 

 thus made closes up, so that the alga is completely cut off from the exterior. 



e 



* Moore, G. T. ** New or little-known Unicellular Algpe : I. Chlorocystis Cohnii:' Bot 

 Gaz. vol. XXX. (1900) p. 100. 



I Reinkej J, *^ Alfienflora der westliche Ostsee deutsche AntheiL«, VI/' Ber. Commiss. 

 Untersuch. deutschen INfeero in Kiel, 1889. 



X Roaenvinge. Ann. Sci. Nat., Bot. 7nie Ser. xix. (1894) p. 161. 



