PHILODINAD^. 101 



ventricose, and marked more distinctly with oblique ridges. The period of tbe con- 

 tractile vesicle is about sixteen seconds. 



It is lively and sprightly. It breeds freely in captivity ; in a phial it congregates at 

 the very margin of the water ; if they are numerous, a glance along the water line with 

 a lens gives a pleasing sight ; it reveals a whole array of tbe tiny creatures hanging head- 

 downward, in the ridge of water produced by the attraction of cohesion, their amber-like 

 bodies of various sizes, and their broad white crown-wheels all in full play. They do 

 certainly appear to have the iustmct of companionship, as Ehrenberg has observed of 

 another species. 



Length, j J jy inch to ^i.y inch. Habitat. Widely scattered, but by no means common. 

 Near London ; Widcombe Pond, Bath ; Tenby (P.H.G.).— P.H.G.] 



P. MEGALOTEOOHA, Ehrenberg. 

 (PL IX. fig. 7.) 



Philodina megalotrocJia . . Ehrenberg, Dio Tnfus. 1838, p. 501, Taf. Ixi. fig. 10. 



„ ,, . . Pritohard, Infusoria, 1861, p. 705. 



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

 wide, with no conspicuous sulcus; antenna three-jointed, unisetate, decurued; eyes 

 large, roundish ; teeth two ; foot slender, abrupt. Hyaline, 



The great width of the expanded corona, and the size of the frontal column and 

 antemia, are very noticeable m this species ; as also the plumpness of the body, and its 

 sudden attenuation to form the foot, whence its appearance is somewhat Uke that of 

 Botifcr macrurus. The spurs are small and the toes short, thick, and truncately conical. 

 The mastax is set more transversely than usual, so as not to be made out in a longitu- 

 dinal aspect. Two teeth cross each ramus. In certain lights there seem to be three ; 

 but a true adjustment with a power of 300 reveals the projectmg points, and shows them 

 to be distinctly two. There is a wide sub-cylindrical stomach with a tubular passage, 

 followed by a short and somewhat transverse intestine. This latter discharges, through 

 a narrow but distinct rectum, beneath the second telescopic joint of the foot. Traces of 

 small globose gastric glands are seen beneath the mastax. A small contractile vesicle 

 lies in fi-ont of the rectum. No other portion of the vascular system has been recorded. 

 The ovary is large with many clear nuclei. The antenna appears to have only one 

 termmal seta. 



Length. About ^^ inch. Habitat. Ponds, ditches, &c. : not uncommon. — P.H.G.] 



P. ACULEATA, Ehrenberg. 

 (PL IX. fig. 5.) 

 Philodina aculeata . . . Ehrenberg, Die Inftis. 1838, p. 501, Taf. Ixi. fig. 9. 



... Dujardin, Hist. Nat. Zooph. 1841, p. G60. 

 „ „ ... Eckstein, Sicb. u. KoU. Zeits. Bd. xxxix. 1883, p. 352, 



Taf. xxiv. fig. 15. 



[SP. CH. Body beset with spines, having no constriction nor swelling at the neck ; 

 corona ?to( so ivide as the body ; antenna two, long-jointed, mobile; eyes lai-gc, nearly 

 round ; teeth tlirec ; foot thick, gradual. Dark brown. 



This species is easily recognised by tlie spines which liave given it a name ; but I 

 cannot find these appendages nearly so numerous as in Ehrenberg's figures.' Nor are 

 they scattered irregularly over tbe body, but are arranged in rows on the dorsal aspect. 

 The first row consists of three spines ; the next two rows have two each, and are placed 



' Ehrenberg draws as many as twenty-seven spines, irregularly placed, on the dorsal surface. 

 Dujardin (apparently following Ehrenberg's description) says that the body is ' tout h^riss^ d'6pines 

 moUes.' Herr Eckstein's description and figure, however, exactly tally with those of Mr. Gosse, only 

 the two spines, which in Mr. Gosse's figures (56, 5d) of the contracted animal point forwards, are 

 drawn pointing backwards in Herr Eckstein's figure of the uncontracted animal. Very likely the 

 direction of the spines is liable to be reversed by the creature's contortions. — C. T. H. 



