PHILODINAD^. 99 



is diflScult to suggest bow this is managed, as there api^ears to bo no communication 

 between the body-cavity and the cloaca.' 



No male has as yet been observed among any of the Philodinadcs. 



P. EEYTHEOPHTHALMA, Elirenherg. 



Philodina erythrophtlialma . . Ehrenberg, Die Infus. 1838, p. 499, Taf. Ixi. fig. 4. 

 ,, ,, . . Pritchard, Infusoria, 1861, p. 705, pi. xxxviii. fig. 4. 



[SP. CH. Body smooth ivith a thick bulging collar ; corona ample with a broad 

 shallow sulcus ; frontal column having no prohoscis ; antenna dccurved, three-jointed ; 

 eyes conspicuous rond-ovate; teeth tivo; foot stout gradual. Animal hyaline, colourless. 



The characters assigned to this and the followig species must not, I confess, be 

 pressed with minute exactitude ; nor are they all of equal value. Some of the species 

 do not differ very obviously infer se. Still, I think, all are specifically distinct ; and the 

 cumulate character, which, with some thought and care, I have assigned to each, may 

 aid the scient in discriminating forms too easily confounded. 



This first species of the genus is one of the most difficult to be diagnosed with pre- 

 cision ; though it is of conspicuous size, and of so common occurrence as to fall very 

 early mider the notice of the student. It was almost the first of the Eotifera ^ which 

 I essayed to describe and delineate, nearly seven-and-thirty years ago, from specimens 

 obtained in the north suburbs of London. 



The most readily observable feature is, that below the corona, itself of ample dimen- 

 sions, there is a thick prominent neck, bounded by sensible constrictions. Thus it seems 

 inseparable from Professor Ehrenberg's P. collaris ; and, indeed, I shrewdly suspect 

 these to be but one and the same species, in different stages of growth. The gradual, 

 instead of sudden, transition of the trunk into the stout foot, is another character easily 

 noticed. The proboscis, which in this family is general at the tip of the frontal column, 

 seems, here, wholly wanting ; the truncate tip having only a slight transverse depression. 

 But the pomt is peculiarly difficult of determination in this species. 



The specific name, besides being repulsive from its uncouth aggregation of unpro- 

 nounceable consonants, is unsuitable, because undistinctive. The possession of red eyes 

 is common, not only to all Pliilodince, but almost to all Eotifera. 



Length, y J^j inch to ^^ inch. Habitat, weedy pools, widely distributed : common. — 

 P.H.G.] 



P. EOSEOLA, Ehrenberg. 



(PI. IX. fig. 4.) 



Philoditia roseola .... Ehrenberg, Die Infus. 1838, p. 499, Taf. Ixi. fig. 5. 

 „ Pritchard, Infusoria, 1861, p. 705, pi. xxxv., fig. 490. 



[SP. CH. Body smooth, tvith no constriction nor swelling at the neck ; corona 

 moderate, with a deep square sulcus ; antenna two-jointed, nearly horizontal ; eyes small, 

 oblong, oblique; teeth two'^ ; foot stout, gradual. Translucent, ruddy in hue. — 

 P.H.G.] 



No doubt it was this common and hardy species which Leuwenhoek discovered in 



' See footnote, p. 103, for a suggested explanation of the difficulty. 



» [It was the second. Euchlajiis dilatata was the very first. — P.H.G.] 



' Lord Osborne kindly sent me many beautiful specimens of the trophi of P. roseola, which he had 

 mounted both plain and tinted %\-ith carmine. They were in every possible position, so as to admit of 

 a thorough study of the jaws. Among these I found several with two teeth only in each ramus, and 

 a few with two in the one and three in the other. I am aware that, when not accurately focussed, this 

 appearance will be sometimes improperly obtained ; but I took care, by delicate focussing, to be able to 

 count the pointed ends of the teeth in each case. Dr. Oskar Schmidt has noticed the same thing in 

 Rotifer vulgaris (Archiv f. Naturgcschichtc, xii. Jahrg., 1 Bd. 1846, p. 69, Taf. iii. fig. 4).— C. T. H. 



I 2 



