I KK8HWATER ALQJR OF THE SOUTH <>l: KNOTS. Ill 



prolong'' "t vrrs les extre"mit<$8 en arfite saillantc," according to Cbodat, p. 146; "An 

 I "-i.il -ii Kmlen iles Zellinhnh* findrn sich Vorspriinge . . . sicherlich nur dadurch 

 (iit-tan. l.-ii, doss die Rippen der Membrun etwas voreprangen," according to Wille, pp. 

 f, also my fig. 23), and, lastly, the apparent formation of new individuals 

 by suMivision of the cell-content*. 1 



(/) CHODATKLLA BRKVISPINA, n. sp. (PI. I., figs. 25, 26 ; PI. II., phota. 3, 5, CA). 



A very typical and rather abundant member* of the yellow snow flora is constituted by 

 spiny i-llipsnidal cells, which appear to belong to a new species of CJiodatella, which may 

 be styled C, brevi*pina (PL I., figs. 25, 26). The cells of this species are discoid and 

 al>out 18 M long and 12 A broad, and are covered all over their surface with uniformly 

 distributed spines. The latter are very short and, as a general rule, do not project beyond 

 the surface for a distance greater than twice the thickness of the wall ; they are mostly 

 rather delicate, but occasionally individuals bearing coarser spines were to be found. 

 All the spines on a given cell are generally of about the same length, although some- 

 times slight differences are noticeable. The cell-membrane is colourless, and consists of 

 two well-marked portions, a dark-looking outer (probably cuticular) layer and an inner 

 much lighter layer. There appears to be a single chloroplast, although I do not feel 

 certain of this ; a pyrenoid was not observed. Large quantities of fat are almost 

 always present in these cells. In the majority of cases two more or less rounded 

 masses are found, one at each end of the cell and separated by a central mass of granular 

 protoplasm in which a considerable amount of starch frequently occurs (PI. I., fig. 26). 

 < >lt rn one of these two fat-masses is considerably larger than the other, and occasionally 

 only one large mass is present at one end of the cell. In some individuals, lastly, the fat 

 predominates to such an extent that only a small amount of granular protoplasm can be 

 distinguished, all the remaining part of the contents being obscured by the accumulation 

 of fat (PL I., fig. 25). 



The greatest difficulty in the way of a satisfactory determination of this form as a 

 species of Chotlnti'lla lies in the absence of all reproductive stages. In Chodatella J 

 reproduction is effected by subdivision of the cell-contents to form a number of new 



1 Wille (lor. fit., p. 171) lso xiiggeatA on the basis of hi* observation* that it may become Decenary to remove 

 /'. niru/u from the genui Ptmaumat ; this i* ba*ed on his view that the ordinary winged cell* are aplanospore* 

 (refeling-celU), that reproduction U effected by small (uniform zoospores, and on the possibility of the cell* containing 

 (everal chloroplatU without pyrenoid* (*ee lot. eit., p. 169). It doe* not appear that the hut of lhe*e observation* U 

 correct ; the others have already been criticiaed above. 



Wille ragged* that the oval evil* provided with longitudinal ridge*, referred to by l<agerhcim an having lieen 

 found in red snow from Amiterdamu (Spitsbergen) (</. footnote 1 on p. 108), were individual* of P. mra/u. A* elated 

 in the footnote on p. 100, I am of opinion that they may belong to the genui Srotiflla, but it hardly Hni* likely 

 that they represent P. niwtlu. The rather vague de* ri|.t I..M |>ints more to a form like Sroftetfu polypiau. 



I'ntil we know more about the movement referred to by Chodat, it aeem* advisable to leave /'. rniWu in ito 

 ptwu-nt genii*. 



Thi form i* much commoner than Sntirlla antardu-<i, but owing to ita (mailer MI* not nearly *o (Inking. 



* E.Lemmermann,"Beitr. /. Krimin . d. Planktonalgvn," I., IMmifia, xxxvii., 1896, p. 300. Chodat, lac. !., p. 101. 



