110 THE IIOTIFEEA. 



the term, very wild, shooting ahout with swiftness in an impatient manner, with a 

 peculiar mingling of swimming and creeping ; proceeding in this way all about the live- 

 box by the hour together, so rapidly and irregularly that the motion of the stage can 

 scarcely keep it in the field. It is much bolder than the other members of the family, 

 keeping its wheels in rotation all the time it is attached ; and though a sudden jar, or 

 the impact of another animal, will cause it to close them, it is but for an instant. I 

 have never seen it contract on alarm into a short round bulb ; far less remain quiescent 

 in such a condition for hours, as Botifer and Philodina do. It is spindle-shaped, the 

 central region of the body always having an angular prominence ; but this varies its 

 situation, sometimes the upper part, sometimes the middle, sometimes the posterior of 

 the abdomen, projecting, according to the position of the viscera at the moment ; the 

 creature thus assumes various candelabra-like forms, as shown in figs. 8, 8a. The head, 

 when extended, terminates in a thick rounded column which is ciliated ; when the wheels 

 are expanded, the column appears small, square, and truncate, fits in below the wheels, 

 and does not project beyond their surface. The foot is moderate in length ; the spurs 

 of the penultimate joint are very minute cones, and the last joint has one small stiff 

 point behind, and two soft cylindrical protrusile lateral toes, truncate at their extremities. 

 The whole surface of the body is covered with minute irregular and close-set corruga- 

 tions. The buccal funnel is very long, and the rami, which are very small, are each 

 crossed with two teeth. A scarcely appreciable oesophagus leads to an enormous and 

 very mobile stomach : in one specimen this organ appeared to be composed of a number 

 of spherical cells ; in others of a minutely granulated texture : it ends in a short 

 rectum. 



There are two corrugated glands in the foot, and a contractile vesicle (whose period 

 is forty seconds) with the usual lateral canals. A long ovary with double rows of rudi- 

 mentary ova occupies each side of the stomach, and two large eggs are commonly seen, 

 of a bright pellucid appearance, but sometimes dark and granulate. The whole animal 

 is crystalline, and usually colourless, but I have seen a specimen in which the wheels 

 were of a delicate pale citron-colour, and another in which the intestine was of nearly 

 the same cinnabar hue as in Philodina roseola, though not so brilliant. It is note- 

 worthy, seeing that the creature is eyeless, that the specimens which I first possessed 

 had been kept in the dark ; expressly because " it was found speedily to die, if kept in 

 the light." With the phial of water I obtained, I impregnated two vessels, one of which 

 I placed in a window, the other in a dark corner. Five months elapsed, when, on 

 examination, the species was abundant in the darkened phial : but in that in the window 

 I could not find a single specimen. 



Length. About J s inch. Habitat. Pools on Hampstead Heath ; lake in Kew 

 Gardens (P.H.G.).— P.H.G.] 



C. pabasitica, Giglioli. 



(PI. X. fig. 9.) 



Callidina parasitica . . . Giglioli, Quart. J. Micr. Sci. N. Ser. vol. iii. 18G3, 



p. 237, pi. xi. 



SP. CH. Spurs stout, conical, as long as width of the contracted joint ; teeth two. 

 Parasitic on the limbs of Crustacea. 



This species was discovered by Mr. H. Giglioli as an epizoic parasite on the thoracic 

 and abdominal appendages of Gammarus pulex and Ascllus vulgaris ; and was figured 

 and elaborately described by him he. cit. According to Mr. Giglioli the body is very 

 transparent and colourless, fusiform in shape, and without the angular prominence at 

 its central region which is so distinct in G. bidens. The corona consists of two small 

 circlets of short cilia, and is rarely expanded ; the animal usually contenting itself with 

 crawling like a leech over its host. There is a distinct alimentary canal surrounded by 



