SYNCIl/ETAD.E. 125 



Genus SYNCH.ETA. 

 GEN. CH. FoTmuS'iially that of a long cone lohose apex is the foot; front furnhltfd 

 with two ciliated auricles; ciliary wreath of interrujHed curves ; foot minute, furcate. 



Though this genus consists of only a few species yet it is alike interesting in its 

 structure and its habits. The various species differ from each other chiefly in the shape 

 of the body and of the coronal head, as well as in the number and position of the tactile 

 organs. There is, too, at least one species which is marine, and which has been said by 

 its presence to render sea-water luminous. 



In all the species the striking characters are the swift and varied motions, the ciliated 

 auricles, the huge niastax, and the long delicate oesophagus closely resemblhig that of 

 Asplanchiia. 



S. PECTiNATA, Ehrenberg. 

 (PI. XIII. fig. 3.) 



Syncliata pcciinata . . Ehrenberg, Di'c In/ws. 1838, p. 4.S7, Taf. liii. fig. 1. 



SijncUata mordax . . . Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 200. 



Synchaita pectinata . . heyiig, Ueb. d. Ban d. Raderth. lS5i, ly. il. 



Sijnchcsta mordax . . . Pritchard, Infusoria, 1861, p. 086, pi. xxxiii. fig. 422. 

 „ „ . . . Hudson, Mon. Micr. J. vol. iv. 1870, p. 26, pi. Ivi. 



SP. Cn. Body a swollen cone; auricles very long, I'ointcd, nsualbj pendent ; 

 coronal head very large and convex; two cluh-sliapcd prominences in front, each 

 crowned with a wide brush of seta ; four styles, the outer pair sometimes compound. 



This is the finest and most vigorous of the Synchcetce. No one can watch it 

 swimming in ample space, without marvelling at the energy of this living speck, and 

 admiring the grace and ease of its varied motions. No swift is more untiring in its 

 flight. Now it sweeps along in spiral turns from the surface to the bottom, and now it 

 darts through the green branches of the water crow-foot to hang motionless over a leaf 

 like a hovering fly m summer ; motionless, and yet with its front all ringed with the 

 halo of its furiously lashing cilia. The auricles, which seem mere rudimentary stumps, 

 are really most efl'ective organs of locomotion. They are tongue-shaped fleshy pro- 

 tuberances, edged with powerful ciha ; and, as they can be set by special muscles at 

 various angles to the body, the creature can dart, wheel, and stop, with the greatest ease. 

 The trunk, seen ventrally, appears to be a cone tapering to a small foot divided into two 

 minute toes, but the side view shows the dorsal surface rising behhid the head into a 

 distinct hump. The coronal head is nearly half a spheroid. Round its base on the 

 dorsal side are four semicircular curves of small cilia, and two similar curves edge cup- 

 like protuberances on the ventral side. These cups can be lowered or raised a little at 

 will, and their contour altered so as to enable their fringe of cilia to sweep the food 

 effectively between the two into the buccal orifice. This Ues near the top of the coronal 

 head towards the ventral side. It can be seen only by looking directly at the top of the 

 head ; no dorsal or side view will show it, and, unluckily, these are the only views that a 

 compressorium will yield. I have, however, on one or two occasions found a Synchata, 

 left in an open cell, swimming feebly in an upright position just before it died ; and I 

 have thus caught sight of the buccal orifice. It is an oval opening between the ventral 

 cups, and overshadowed by two projections each bearing a fan of styles. As the atoms 

 of food are swept towards the orifice, the fans are bent over it, and the styles lash the 

 water to drive downwards any escaping prey. Many Rotifera have a similar contrivance, 

 notably tlie Brachioni, whose coronal st}les form quite a dome over the buccal orifice. 

 The corona bears also four tactile organs, two towards the dorsal, and two towards the 

 ventral side ; and each consisting of one or more styles issumg from a small prominence, 

 and set in a short cylinder. To the end of the cylinder a muscle is attached, so that by 

 this means the styles it carries can be withdrawn nearly below the surface. There is 

 yet another organ of toucli. At the summit of the dorsal hump met't two rocket- 

 headed antennae, each liearing a tuft of setie ; and the two tufts issue together from the 



