274 ORDER FLAGELLATA-PANTOSTOMATA. 



The animalcules relegated to this family group closely coincide with those of 

 the Dendromonadidae last described, but are to be distinguished from them by their 

 secretion of horny loricne and normally transverse mode of fission ; the relationship 

 of these two groups is consequently closely parallel with that which subsists between 

 the naked and loricate sections of the Vorticellidse. 



GENUS I. HEDR^OPHYSA, S. K. 



(Greek, hedraios, sessile ; physa, bladder.) 



Animalcules solitary, irregularly ovate, possessing a more or less con- 

 spicuous anterior lip-like prominence, inhabiting horny sheaths or loricae, 

 which are attached in a sessile manner, without an intermediate pedicle, 

 to subaquatic objects ; flagella two in number, unequal, one long and one 

 short, originating close to each other near the centre of the anterior border. 



The representatives of this genus differ from those of Bicosoeca merely in the 

 absence of a supporting pedicle to the lorica. A single species, inhabiting salt 

 water, has as yet been observed. 



Hedraeophysa bulla, S. K. PL. XVIII. FIG. 24. 



Lorica subglobose, bubble-like, anterior aperture of small dimensions ; 

 animalcule occupying the greater portion of the cavity of the lorica, 

 attached in a sessile manner to its bottom ; height of lorica 1-4000". 



HAB. Salt water. 



A single example only of this species has been so far met with, being then 

 obtained by the author attached to Conferva from- sea-water collected at St. Heliers, 

 Jersey. 



GENUS II. BICOSCECA, James-Clark. 



Animalcules solitary, more or less ovate, with a projecting anterior lip- 

 like prominence, inhabiting simple, pedicellate, horny loricae, to the bottom 

 of which they are attached by a thread-like contractile ligament or peduncle; 

 flagella two in number, unequal, one long and one short ; an endoplast and 

 one or more contractile vesicles usually conspicuous ; no distinct oral aper- 

 ture, food being incepted at all points of the periphery. Increasing by 

 transverse fission and by the subdivision of the body into spores. 



As first described by Professor H. James-Clark, the members of this genus were 

 represented as possessing a single vibratile flagellum only. The existence of a 

 comparatively minute' secondary one has, however, been clearly demonstrated by the 

 author on innumerable occasions, and in connection with a variety of specific types. 

 The homologue of a secondary flagellum has been supposed by Professor Clark to 

 exist in B. lacustris in the posterior eccentrically developed contractile ligament 

 which fixes the animalcule to the bottom of its lorica, and which in such case he 

 maintains favours the interpretation of Bicostxca as a thecated Heteromita or Aniso- 

 n cm a permanently affixed in its sheath by the trailing or gubernaculate flagellum. 

 That Bicosceca originates from a motile Heteromitous zooid is shown by the author 

 in the following descriptions of B. lacustris and B. pociilum ; but the accompanying 

 demonstration of the existence of two vibratile flagella, in addition to the contractile 

 ligament, during the more normal sedentary conditions of these species, entirely 

 negatives Professor Clark's hypothesis. In Bicosoeca pocillum, more especially, the 



