PHILODINAim 



105 



Rotifer tardus 



R. TARDUS, Ehrenberg. 

 (Pl.X. fig. 1.) 



Ehrenberg, Die Infus. 1838, p. 490, Taf. Ix. fig. 8. 

 Pritchard, Infusoria, 1861, p. 704. 



Eckstein, Sieb. u. Kull. Zeits. Bd. xxxix. 1883, p. 358, 

 pi. xxiii. fig. 13. 



[SP. CH. Trunk dull brou~n, viscous, with foreign bodies attached, corrugated 

 longitudinally and transversely ; extremities colourless ; dorsal antenna swollen at the 

 top, large; spurs long ; eyes shaped like long drops, usually broken; teeth tivo. 



This is a large sluggish Rotifer of clumsy build, fond of groping among floccose 

 sediment, or of getting within the hollow bracts of a moss and of remaining snugly 

 ensconced there for some time. It frequently appears contracted, the constrictions 

 alternating with prominent swellings, like a sack tied in many places, while the body is 

 fluted almost as regularly as an Ionic column ; and its whole surface is covered with a 

 viscous secretion to which floccose matter, small Diatoms, &c. attach themselves ; 

 sometimes a long stream of the mucus is dragged behind, with extraneous substances 

 adhering. The colour appears to be wholly external, and to depend, in some degree, 

 on the extraneous matters lodged in the viscous coating ; for those portions that are 

 constantly introverted are free from surface-colour, though the viscera have still a slight 

 yellow tint. The corona is large and powerful, and the frontal column is cylindrical, 

 truncate with a minute proboscis at the tip, which does not seem sensibly hooked, or 

 even lengthened, and which projects between and over two small disks each carrying a 

 wreath of vibrating cilia. Within the column, and at some distance from its tip, are 

 the eyes, 1 which are usually long and drop-like in shape, and often broken 2 one eye often 

 more than the other. The body tapers gradually to the foot, the last joint of which ends 

 in the usual three toes, of which the hindmost is the shortest ; all these are curved and 

 claw-like, but truncate. The penultimate spurs are much developed. The dark colour 

 of the trunk, and its close-set corrugations, nearly destroy its transparency, so as to 

 make it very difficult to demonstrate the viscera. By pressure, however, on one occasion, 

 the intestinal canal was forced out, attached to the mastax, the ligaments of the anal 

 extremity having given way ; it appeared then as at fig. Id ; a slender tube, permeating 

 a thick cellular mass, forming the stomach. The mastax has two distinctly separated 

 teeth in each ramus. I cannot but think that B. citrinus and B. tardus of Ehrenberg 

 are one and the same species. " 



Length. When fully extended, up to -% inch. Habitat. Near London ; Snaresbrook ; 

 Birmingham; Woolston ; Dundee (P.II.G.) : not uncommon. P.H.G.]. 



R. MACROCEROS, GoSSC. 



(PI. X. fig. 5.) 



Rotifer macroccros 

 Rotifer Motacilla 



Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 202. 

 Bartsch, Die Raderth. b. Tubingen, 1870, p. 48. 



Rot. Hungarice, 1877, p. 27, iv. Tib. 34 abra. 



[SP. CH. Body hyaline with longitudinal folds ; corona large; spurs short, stout; 

 dorsal antenna very long and mobile ; eyes small, round ; teeth two. 



This form, which I discovered in 1850, and described in " Ann. Nat. Hist. " 

 September 1851, is indubitably a good distinct species. It has occurred repeatedly of 

 late. The great length of the antenna, being not less than fully one-third of the whole 



1 If, as I suspect, the Rotifer which Dr. Leyclig describes as Rotifer citrinus is really R. tardus, 

 then each of the eyes of the latter Eotifer (according to Dr. Leyclig) has a crystalline light-refracting 

 body imbedded in the pigment. P. H. G. 



2 Herr Eckstein (loc. cit. Taf. xxiii. fig. 12) has noticed a similar anomaly in Rotifer vulgar is, and 

 Ehrenberg has seen another case in R. mac.rurus (loc. cit. Taf. Ix. fig. 7J. 



