ip ^ f-^' 



16 MISS B, M. BRISTOL ON 



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VIII. Chlorochytpjum Sakcopiiyoi (VVhitting), G. S. West. 



This species, though evidently bearing a very close resemblance to C. 

 inclusum^ Kjellni,, must certainly be regarded as an independent species on 

 account of its destructive action on the fronds oE SarcophyatSj in which it is 



;m endophyte. The alga causes at first a swelling and loosening of the 

 tissue in which it lives, and finally a complete disintegration of the cells, 

 which may result eventually in the formation of circular holes in the frond. 



The cells are described * as uniformly thin -walled, and irregular in shaj^je 

 according to the pressure of the thallus. Spores^ 100 or more according 

 to the size of the cell, are produced by free cell-formation ; or in some cases 

 the protoplasm is segmented into portions wdiicli are of a considerably larger 

 size than the spores, and Avhich, though uniform in size, are irregular in 

 shape. Owing to the fact that only preserved material was examined, the 

 exact nature of these larger segments was not determinedj but it w\as 

 suggested that tliey might be produced by a preliminary segmentation of the 

 protoplasm before the final formation of the small spores^ or that there might 

 be two kinds of spores comparable to those observed in C, Moorei^ of wdiich 

 these might be the lariicr. 



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w 



IX. Chlorociiytrium Cohnii, E. P. Wrioht. 



This species, described first by Wright f in 1877, has been the subject of 

 greater controversy than any other species of the subfamily. Unfortunately, 

 Wright's original description is so full of obvious errors of observation tliat 

 his description is of little real use in the subsequent identification of his 

 species. He describes the cells as circular in outline, usually imbedded 

 completely in the host except for a small nipple-shaped projection from 

 the surface of the frond. In cases where the cells are developed entirely 

 within the tissues of the host they are destitute of the projection from the 

 cell-wall. The cells contain a single pyrenoid, but Wright's description of 

 the chloroplast is such that it is impossible to understand the nature of the 

 cell-contents. Eventually, by free cell-formation, 10-30 or more zoorronidia 



are formed, each possessing^ according to Wright^ a single cilium. The 

 7:oogonidia are of two kinds, large and small, and on impinging on the frond, 

 quickly assume a figure-of-eight form, the lower sphere growing into the 

 frond and assuming large dimensions, and the upper portion remainino- as a 

 short tubular neck. 



Lagerheim's paper on C. Cohnii, E. P. Wright J, published in 1884, can 



* Whitting, F., in G. Murray, Phyc. Mem, Part II. p. 13. 



t Wriglit, E. P. "On a new species of parasitic green Alga belonging to the genus 

 Chlorochi/trimn of Colin." Trans. Roy. Irish Acad. voL xxvi. p. 355. 



X Lagerheim, G. " Oni Chlorochytrifim Colmii^ Wright." Ofversigt af Kongl. Vetenekaps- 

 Akademiens Furliandlingar, 1884, No, 7. Stockliolm. 



