Chcetopeltidece 



183 



probably, however, it is but a small variety of Ch. globosum with the cells 

 9 12 p. in diameter 1 . 



Genus Conochsete Klebahn, 1893. The cells are comparatively 

 small, loosely aggregated, and embedded in a small amount of 

 mucus. Each cell is sub- 

 globose, often depressed, 

 and possesses a number 

 of delicate bristles which 

 radiate in all directions. 

 Each of the latter arises 

 either from the apex of 

 a mamillate protuberance 

 of the cell-wall or from 

 the base of an elongated 

 sheath. There are one or 

 two chloroplasts in each 



Fig. 71. A form of Conochate comosa 

 Klebahn, from the New Forest, Hants. ( x 370). 

 ch, chloroplast ; o, oil-globule. 



cell, each furnished with 

 one pyrenoid. The cells are markedly dorsiventral and sometimes 

 a prominent oil-globule is present in the basal half of the cell. 

 The plants multiply by cell-division in two directions and by 

 zoogonidia, of which four or eight are formed in each cell 2 . 



Two British species are known, both of which are exceedingly rare. 

 C. comosa Klebahn possesses cells 13 26 /u in diameter and the bristles, 

 which are 3 5 in number, are sheathed at the base (fig. 71). C. polytricha 

 (Nordst.) Kleb. possesses cells 10 16 p. in diameter and the bristles arise 

 from the apices of a number of mamillate protuberances of the cell-wall, the 

 latter exhibiting a well-marked stratification. 



Genus Polychsetophora West & G. S. West, 1903. The 

 plants are unicellular or sometimes composed of short, loosely 

 connected filaments of six or eight cells. The cells are subglobose 

 or ovoid, and the cell-walls are exceedingly thick and lamellose. 

 From the outer layers of this lamellose cell- wall from 8 to 12 long 

 flexuose bristles are given off. The bristles are very delicate and 

 attenuated to fine points ; they are quite simple, without any trace 

 of a basal sheath or any basal swelling, and they radiate in every 

 direction. Sometimes the cell-wall is unequally developed, a large 

 stratified outgrowth having been developed on one side. Such a 

 cell has a stalked appearance which presents many points of 



1 This small form is known from N. Yorkshire ; vide West & G. S. West in 

 Trans. Yorks. Nat. Union, 1900, vol. v, p. 22. 



2 Schmidle in Hedwigia, 1899, p. 162, t. vi, f. 1619. 



