12G THE ROTIFER A. 



same opening. A nerve-thread passes from each rocket-head to a nervous ganglion in 

 the head, on which is seated a bluish-purple eye-spot ' bearing a refractive body, shaped 

 somewhat like a truncated cone. 



The great mastax is a pear-shaped body placed so close to the buccal orifice that 

 there is no room for a buccal funnel. The forcipate tropin are driven snapping through 

 the buccal orifice by the great striated muscles shown in fig. 3. A V-shaped one 

 embraces the end of the fulcrum, and one on each side acts on each malleus. The 

 oesophagus closely resembles that of Asplanchma, and like that is often used as a supple- 

 mentary stomach. Indeed, I have seen it so full that, for a moment, I did not recognize 

 Synchceta, and thought that I had found a new Eotiferon. The gastric glands are 

 small and round ; the foot glands obvious. The stomach is usually yellow, but sometimes 

 brown ; more rarely, pink. It is round, with thick walls formed of very large cells. 

 Sometimes these are studded all over with oil-globules, as in fig. 3. The lateral canals 

 with their vibratile tags can be plainly seen in the lower half of the trunk, but do 

 not appear to run up to the head in the usual fashion. There is a small round contrac- 

 tile vesicle just above the foot. The longitudinal and transverse muscles, as well as 

 those that work the auricles, can be seen in fig. 3, and need no further description. 



The male is as yet unknown. 



Length, ^ inch. Habitat. Clear ponds and reservoirs : common. 



Syn< ii.y.TA P.altica, Ehrenberg. 

 (PL XIII. fig. 1.) 



Synchceta baltica Ehrenberg, Die Infus. p. 437, Taf. liii. fig. 5. 



Gosse, Tenby, p. 274, pi. xiv. 



[SP. CH. Body cylindric, becoming conical behind, or bell-shaped: gibbous 

 dorsally ; rotatory clusters /owr, : styles four; crest single, sessile. Luminous. Marine. 



The form is usually that of a bell, or a long cone, viewed dorsally ; but much arched, 

 viewed laterally. The auricular lobes are very small : two equidistant setaa radiate from 

 the occiput. There are two ciliated eminences besides the auricles, and a medial crest, 

 smooth-edged. The front is rather wider than the body, whose hinder part tapers to a 

 well-jointed foot, and two very minute conical toes. Conspicuous pear-shaped mucus- 

 glands from these run up through the foot. 



A large red eye is seated at the end of a cylindrical brain-sac : below which is the 

 vast mastax of normal structure. We see, now and then, a momentary snatching 

 action with this organ, of which I have not been able to define the actual seat. A 

 sudden trembling also occasionally passes through the whole fore parts. A long 

 oesophagus leads to a small sacculate yellow stomach, on which are seated ample gastric 

 glands. A small intestine opens into the cloaca, above which projects a wart, which is 

 a true tail. A band-like ovary, of horseshoe form, the ends forward, lies in the lower 

 belly ; and behind this a small contractile bladder, whose period is %\ times a minute. 

 The muscular system is very distinct : a cord from the frontal region is inserted in the 

 skin of the back, thrown into sigmoid curves during contraction ; other cords proceed 

 from the hind-head to various points near the middle of the trunk ; one (pair?) proceeds 

 from the mid-back to the side ; five or six bands run transversely across the back. There 

 are, moreover, long diagonal bands down the sides. 



The brilliant translucency of this animal makes it a very charming object, particu- 

 larly when well illuminated on a dark ground, when the eye shines out like a ruby, and 

 the whole body resembles a sparkling diamond. Its movements are vivacious and 

 elegant. It shoots rapidly along, or circles about in giddy dance, in company with its 

 fellows, sometimes near the surface, sometimes just over the bottom of its prison. Occa- 

 sionally the foot and tiny toes are drawn up into the body, and then suddenly thrust 

 down, and bent up from side to side, as a dog wags his tail. Sometimes the two ear- 

 1 Crimson by lamp-light and dark-field illumination. 



