BUG. 



[ 123 ] 



BULBOCH^ETE. 



BUG. See CIMEX. 



BU'GULA, Oken (Cellularia part, John- 

 ston). A genus of Infundibulate Polyzoa 

 (Bryozoa), of the suborder Cheilostomata, 

 and family Bicellariidse. 



Distinguished by the elliptical closely 

 contiguous cells in two or more rows, the 

 very large orifice with a simple not thick- 

 ened margin, and the stalked, jointed, fre- 

 quently blue or red avicularia. 



B. jlabellata. Cells in many rows, ob- 

 long, truncate at ends, with one or two 

 spines at upper angles ; orifice extending to 

 the base ; avicularia on the sides of the cells 

 capitate, surface smooth ; ovicells cucullate, 

 with a very wide orifice. 



B. avicitlaria (Cellularia avic., Johnston). 

 Cells in two rows, elongate, contracted 

 below ; orifice not reaching quite to the 

 base, obovate ; with two spines on the outer 

 side, and one on the inner above ; avicularia 

 lateral, capitate, surface granular or areo- 

 late ; ovicells superior, subglobular : orifice 

 small. Deep water. 



B. plumosa. Cells elongate, narrowed 

 below, with a spine at upper and outer angle ; 

 orifice as wide as the cell above, elliptical 

 below; avicularia capitate, close to outer 

 margin of the orifice ; ovicell superior, glo- 

 bular. 



B. Murrayana (Flustra Mur., Johnst.). 

 Cells in many rows, narrowed about the 

 middle and below ; orifice oval, with one to 

 four incurved marginal spines on the outer 

 and one on the inner edge ; a strong hollow 

 spine on each side of the top of the cell, and 

 a capitate avicularium on the front of some 

 of the cells below the orifice. Very rare. 



BIBL. Busk, Mar. Polyzoa (Br. Mm.\ 

 43 ; Johnston, Br. Zooph. ; Hincks, Potyzoa, 

 73. 



BULBOCHJE'TE, Ag. A genus ofCE- 

 dogonieae (Confervoid Algse), distinguished 

 by the branched habit, and by the cells re- 

 sembling bristles with a bulbous base situ- 

 ated at the tips of lateral shoots. They 

 form villous tufts 1-4 to 1-2" high on fresh- 

 water plants in lakes and pools. 



The cells of the main filament multiply 

 in the same way as those of (EDOGONIUM:, 

 under which head the process is minutely 

 described. The parent-cell breaks by a cir- 

 cumscissile dehiscence to allow the expan- 

 sion of the two new cells. The bristles which 

 are formed at the upper ends (alternately 

 on each side of the filament, fig. 83) like- 

 wise break out from a slit in the cell from 

 which they arise. The bristle is sometimes 



Fig. 83. 



sessile on the cell from which it arises ; 

 sometimes multiplication takes place at its 

 base, so that one or more cells are inter- 

 posed ; the bristle is always the oldest part 

 of the branch. 



These plants are 

 multiplied by zoo- 

 spores, and by rest- 

 iug-spores formed 

 after fertilization 

 by the contents of 

 antheridial cells. 

 The zoospores are 

 formed from the 

 whole contents of a 

 globular or oval 

 cell produced be- 

 tween the bristle- Bulbochsete setigera. 

 cell and the cell on Portion of a filament ^ a 



which it IS attached, sporiferous cell. 



Which dehisces by Magnified 150 diameters. 



a circular slit, causing the upper part with 

 the bristle to separate, and allowing the 

 single zoospore, crowned by a wreath of 

 cilia (as in GEdogonium}, to escape into the 

 water, where it moves actively for a time, 

 acquires a cellulose coat, and then germinates 

 into a new filament. We have not space to 

 give the details of the development of the 

 parent-cell of the zoospore, which, however, 

 are very interesting. 



The resting-spores are formed, in the first 

 place, somewhat in the same way and in the 

 same situations as the zoospores; but the cell- 

 contents do not escape. An orifice is formed 

 in the wall of the parent-cell, through which 

 the spermatozoids coming from the anthe- 

 ridia penetrate. The spore-mass then be- 

 comes encysted ; and its contents are changed, 

 the green colour arising from the presence 

 of chlorophyll giving place to a brown tint. 

 The resting-spore ultimately escapes by the 

 rupture of the parent-cell (oogonium, Prings- 

 heim) ; and in its germination (in the fol- 

 lowing season) the contents are developed 

 into four zoospores, which escape from the 

 spore-membrane and grow up singly into 

 new plants (PI. 5. fig. 22). 



The history of the antheridia of the CEdo- 

 gonieae is somewhat complicated. In the pre- 

 sent genus, a few short cylindrical cells are 

 developed underneath the bristle-cell, either 

 on special branches or on the sporangial 

 branches, between the parent-cell of the 

 spores and the bristle. These cells break 

 by circumscissile dehiscence, and discharge 

 their contents in a form exactly resembling 

 the vegetative zoospores, but much smaller. 



