124 THE KOTIFEKA. 



Genus SACCULUS, Gosse. 



( I EN. CH. Corona with one apex ; trophi inclosed in a masta v, virgate, with unequal 

 mallei, very evanescent; alimentary canal very large, having eight cceca; eggs attached 

 afte) deposition. 



S. viridis, Gosse. 

 (PL XI. fig. 2.) 



ulzis viridis . . . Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 198. 



Ascomorpha helvetica . . Perty, Znr Kcnnlniss kleinst. Lebensf. 1852, p. 39. 



Asa > an intra (?) . Leydig, L'eb. d. Ban. d. Raderth. 1K54, p. -14, Taf. iii. fig. 34. 



viridis . . . Gosse, Phil. Trans. 1857, p. 320, pi. xv. figs. 24-26. 



i morpha saltans (?) . . Bartsoh, Rot. Hungarim, 1877, appendix, Tab. ii. fig. 17. 



This beautiful " little green sac " was first discovered by Mr. Gosse, in the summer 

 of 1850, in a small pool on Hampstead Heath, and was described by him in the "Annals 

 of Natural History" in 1851. It haunts the bottoms of small pools on heaths and in 

 plantations, and I have occasionally found it roaming over the vegetable sediment at the 

 shallow ends of cattle-ponds. It is not a common creature, and it is an extremely 

 difficult one to study, for its skin is thick and rough, and its huge stomach hides almost 

 all the other organs. 



The ciliary wreath is a simple ring of cilia with three or four large styles set in it at 

 intervals. Just below the wreath, on the dorsal side, is a comparatively clear space of 

 external surface (rigs. 2, 26), which is shagreened, as it were, with diamond-shaped 

 clusters of granules. Through this can be seen the nervous ganglion, bearing a crimson 

 eye, and (I think) the front portions of two spherical gastric glands. The ovoid mastax 

 can be readily seen in the side view ; it contains delicate triangular rami on a long 

 slender fulcrum and two rod-like mallei, which Mr. Gosse thinks are of unequal length. 

 The shape of the stomach is very unusual. Seen dorsally it appears to consist of two 

 cylindrical sacs, one on each side, tapering in front, curved towards each other behind, 

 and connected by a broad cross sac, so as to have a rude resemblance to a letter H. A 

 lateral view shows four short, equal sacs hanging down from the long side sacs ; two on 

 each. The whole of this strange stomach is stuffed full of beautiful green oval bodies, 

 which are probably the zoospores of alga?. At each of the four junctions of the short 

 sacs with the long ones there is a dark-brown spot, which seems to consist of decomposing 

 food. No observer has seen any fascal discharge, or detected a cloaca ; and although I 

 made several specimens fast for some hours in clear water I failed to obtain one with a 

 comparatively empty stomach. The ovary lies between the four short caecal prolongations 

 of the stomach, and the contractile vesicle lies deep down below the connecting cross 

 sac. The animal carries its eggs attached to its hind extremity ; bearing sometimes one 

 or two female eggs, or occasionally a whole cluster of small male eggs. 



[From oue of the eggs, which, before maturity, are much clouded and spotted with 

 granules and globules, a young one was produced in my live-box, which was, I doubt 

 not, a male (fig. 2c). I could not detect any eye (though this organ is conspicuous in 

 the parent) nor any internal organisation ; nothing but a confused assemblage of granules 

 and globules ; even the ordinary opaque masses were not present. The form somewhat 

 resembled that of an amphora with a short wide neck ; the frontal cilia were very large, 

 but the motion was not rapid, nor was the animal wild, as male Rotifera usually are. — 

 P.H.G. ("Phil. Trans." he. cit.).] 



Length. Female, y-^ inch ; male, ., !„ inch. Habitat. Hampstead Heath (P.H.G.) ; 

 Clifton (C.T.H.). 



Family VII. SYNCEUETADjE. 



Corona a transverse spheroidal segment, sometimes much flattened, with styligerous 

 prominences ; ciliary wreath a sing le interrupts dor continuous marginal curve, encircling 

 the corona; mas'.ax very large, pear-sJiaped ; trophi forcipate; foot ■minute, furcate. 



