128 TiiK i;()T11'i;i;a. 



S. TREMULA. 

 (PI. XIII. fig. 2.) 



Synchata trenmla . . . Ehicnbeig, DU Inftis. 1838, p. 438, Taf. liii. fig. 7. 

 „ „ . . . I.ejdig. Vcb. d. Ban d. lUidertli. 18.il. p. 41. 



„ „ . . . I'ritchard, Infusoria, 18G1, p. (iSG. 



SP. CH. Boij a slender cone ; C0T0na.\h.ea,d. nearly (rtmcate ; a,UTicles scarcely j)ro- 

 tuherant ; setx four ; no club-shaped prominences; a sudden dimiuution in girth belmo 

 the cloaca. 



S. tremula is rather smaller tlian S.peclinata, mid its habits are different. It loves to 

 twirl round its own loni^'er axis at the end of a thread stretching from its toes ; and, so 

 twisting, to drift lazily along with the cm-rent which bears the object to which it is 

 attaclicd. Its coronal head is almost Hat, and the side amides are nearly in the same 

 plane with it. This makes the animal strikingly unlike S. jiectinata in outline. It has 

 no crests on its corona ; only four long curved styles, similar to those of S. jieclinata. Its 

 stomach is generally full of a rieli brown food, and I have sometimes captured specimens 

 with the oesophagus at the same time stuffed with some pmkish substance. Its eye is an 

 intensely dark-red, and Mr. Gosse has detected a refractive body imbedded in the pig- 

 ment.' There is a rocket-shaped antenna (fig. 2h) on each side of the trunk just above 

 tlie foot : organs that 1 have failed to detect in S. pcctinata. In all other respects the 

 structure of tlio two species is almost identical. 



[In one of the shallow evaporating tanks in my orchid house, I found (at the end of 

 Jlay) this pretty species swarming. It plays, by myriads, just above the dull-green 

 iloccosc sediment that settles on the bottom. I learn, from this colony, a habit which I 

 think has not been recognised as proper to this genus — viz. that, like the Brachioni and 

 Anurecc, and one or two other genera, Synclueta retains its egg after discharge, attached 

 to its own body, just behind the foot. The egg, which I saw, was nearly globular, of a 

 pale yellow hue, granular by the process of segmentation.— P. H. CI.] 



I found the male ( (ig. 2c) in the winter of 1870. It is much smaller than the female, 

 naiTower for its length, but otherwise much like her in shape, and with the same four 

 styles on the coronal head. I distinctly noticed in it the entire absence of the nutritive 

 system ; but its irrepressible energy prevented me from obtaining more than a fleeting 

 view of the sperm-sac and penis. 



Length, yj„ inch. Habitat. Clear ponds ; common. 



' [On the occipital aspect of tlie brain-mass is seated an eye-spot, always conspicuous both from its 

 Ki'eat size and from its intense colour, a red so deep as to be practically black. Its outline varies 

 much ; but normally it is a hemisphere, or rounded cone : often it seems homogeneous, but occasionally 

 we see that it is composed of a nuiltitudc of pigment cells agglomerated together and inclosed within 

 a transparent capsule, whose walls I have freipiently detected of a thickness greater than that of one 

 of the pigment cells. 13ut more than this ; I have seen, so often as to have no doubt of its presence, 

 an ovate transparent cell, let-in, as it were, into the coloured body of the eye, the dark pigment rising 

 on each side so as to embrace the base of it. I venture to think this a crystalline lens. — P.H.G.] 



