174 



BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



Fig. 141. — Cepedea 

 (?) FLAV.\. (Aftek 

 Stokes.) 



CEPEDEA (?) FLAVA (Stokes). 



OpaJina flaia Stokes (1884) 



Host. — Scaphiopus solitm^us Holbrook, onci scant infection in a 

 young individual, date and locality not mentioned, studied by Stokes 

 (1884 and 1888). 



Stokes' description is as follows. — 



Opalina flava, sp. nov. Body ovate, inflated, often as long as broad, or sub- 

 pryriforni, widest and rounded, posteriorly, the length one and one-half times 

 tlie breadth ; the right and left hand borders evenly 

 rounded ; striations of the cuticular surface obliquely 

 disposed and bearing the long, fine, vibratile cilia; 

 nuclei (?) numerous, small, scattered; sarcode enclosing 

 many refractile corpuscles and larger spherical l)odies 

 apparently vacuolar; contractile vesicle none; paren- 

 chyma lemon yellow, the color darkest near the periphery, 

 where it is disposed in a layer, the central portion of the 

 sarcode being comparatively colorless. Length ^j^^ to ^|^ of 

 an inch. Habitat, the rectum of the spade-foot hermit 

 toad, Scaphiopiis holbrooki [S. solitarivs Holbrook]. 



Stokes further says : 



The infusorian is broadly ovate, soft and flexible and somewhat changable 

 in shape, assuming at will a subpyriform or subglobular figure. 



Also: 



Its numbers are not great: perhaps a dozen were noted in the contents of the 

 rectum. Neither is it always to be found. 



Also: 



* * * associated with them was * * * .^ large species of Opalina, 

 whch I have, after some hesitation, identified with 0. ranarum Purk. * * * 

 Their appearance and structure are those of the latter, but the size is much less. 

 They are quite active. As they pressed each other beneath the surface or 

 forced each other upwards, the aspect of the field of view was comically like a 

 pool of furiously boiling soup with big dumplings bobbing about. 



It is difficult to determine what Opalinids Stokes saw in this in- 

 fection. The yellow color emphasized in the name is found in the 

 ectosarc of numerous species, perhaps of all under certain conditions 

 (see Metcalf, 1909). The shape is not adequately described, the 

 word " inflated " being insufficient to let us know whether the bodies 

 were at all flattened, or were even considerably flattened but thick 

 in comparison with the ran arum-like, forms with which they were 

 associated. " Subpyriform " and " subglobose " also are not clear 

 as to the thickness of the animals. Such change of shape as Stokes 

 describes I have not observed in any species, except when an in- 

 dividual is pressed out of shape by some external influence. In- 

 fluenced by Stokes' use of the Avords " inflated," "subpyriform" and 

 " subglobose," I am placing this species as one of the Cepedeas, and 

 am not attempting to determine to what species it is most nearly 

 related. Stokes' description does not fit any form I have studied. 

 The species is of very doubtful validity. 



