OF THE FLOSCVLATII.EA. 



GGo 



considers is a doubtful member of the llotatorial class ; and Leydig suggests 

 that it is probably a larva of some cephalous mollusk. In the propriety of 

 excluding it from amongst the Eotatoria we fully concur. Dujardin and 

 Leydig also transfer Microcodoyi to another family, regarding its caudal process 

 as being a free articulate foot rather than a contractile attached peduncle. 

 Its affinities are unquestionably with Furcularia, Notommata, and Hydatina, 

 rather than with Megalotrocha. 



Ehrenberg's description of the ovum of Megalotrocha alho-fiavicans con- 

 tains some grave errors. He describes the embryo as developing within the 

 germinal vesicle, and growing at the expense of the surrounding yelk, as is 

 the case with a vertebrate ovum. This is so contrary to what occurs in 

 other Kotifcra, in which the entire yelk is directly transmitted into the 

 embryo, that, merely reasoning from analogy, we should be led to reject it. 

 But Kolliker has shown that the embryo of Megalotrocha is developed in the 

 same way as those of other Rotifera. 



Genus MICROCODON. — Eye single ; wreath of cilia simple, bent in the 

 middle so as to resemble the figure 8 lying transversely ; alimentary canal 

 thick and straight, without a stomach ; no oesophageal tube, but a sort of 

 pharyngeal bulb and a couple of single-toothed jaws ; also a turgid ovarium. 

 Immediately behind the rotary apparatus is a small red visual organ ; and at 

 the frontal region, beside it, is a reddish knot whose function is unknown. 



MiCROCODON Clavus. — Campanulate, 



{)edicled, the styliform foot-like tail as 

 ong as the body ; in the middle of the 

 brow are two bimdles of stiff bristles : 

 two pincer-like points, evidently teeth, 

 project out of the middle of the rotaiy 



organ, and are in connexion with the 

 reddish jaws, (xxxii. 371 is a back, and 

 fig. 372 a left side view.) 1-280". 



Perty thinks that the so-called eye 

 consists of two red stripes, beneath which 

 a ribbed body is faintly discernible. 



Genus MEGALOTROCHA. — Eyes two, sometimes becoming effaced by 

 age ; rotary organ has two lappets. The nutritive system consists of a 

 stomach, caecum, rectum, and oesophageal head, having two jaws, Avith teeth, 

 and two glands ; reproductive organs, a short knotted ovarium, with a few 

 ova ; muscles, three pair anterior, two pair posterior, longitudinal ; two con- 

 tractile muscles for the rotary organ, and four oesophageal ; eyes frontal, of 

 a red colour when young ; four circular transverse muscular bands are also 

 seen. The nature of four opaque white spherical bodies at the base of the 

 rotary organ is unknown. 



MEGALOTnocHA alho-flavicans ( Vor- \ or five thus attached, and in process 

 ticella socialis, M.). — White and free ! of further development, (xxxii. 374- 

 when young ; yellowish, and attached in 376 represent difterent specimens ; 377 

 radiating clusters when old. Ehrenberg merely the teeth and jaws separate.) 

 states he has often perceived the red ITpon M^ater-plants. Size of single ani- 

 e3^es within the unbroken egg ; and the I malcule 1-36" ; of the spheres 1-6" 

 jaws, as if in the act of chewing, move j (xxiii. 1). 



laterally and horizontally against eacli M. vehda (Gosse). — Animals separate ; 

 other. Two ova are rarely produced at disc partially enveloped in a cleft, gra- 

 one time ; the egg, when expelled from ! niilar integument ; eggs not attached to 

 the body, remains attached to it by a the parent after deposition. 1-55". 

 thread ; and the parent lias often four | 



FAMILY lY.— FLOSCULARI^A. 



Ilotatoria surrounded by a case or envelope, and provided with a single 

 rotary organ, flexuose at its margin and lobed or divided, having from two to 



