G60 DESCEIPTION OF [Rotatoria. 



lorica is open upon the under side fscidellnmj ; this is distinctly seen 

 in four species ; a compound rotary organ is present in all, over it 

 projects a retractile frontal hook (respiratory tube) ; an oesophageal 

 head with two jaws, in two species with two or three teeth; the 

 o?sophagus very short; two species have a constricted stomach 

 fgasterodela), the others have a simple alimentary canal fcoelogastricaj, 

 all with glands. The red frontal eyes are delicate ; in C. uncinatus 

 and C. biciis^nclatus they have escaped observation ; all have peculiar 

 vesicles at the back. They resemble Monura. 



CoLTJKXJS (?) uncinatus {Brachionus uncinatus, M.) — Lorica ovate, 

 compressed, posterior and bi-pointed toes, very short ; at the middle of 

 the back is generally a cu'clet of vesicles, which at one time Ehren- 

 berg considered eyes, but he now regards them as vesicles of oil, as 

 they are seen in all the species, and abundantly in the Cychpida. 

 Found both in fresh and sea water. Length l-430th to l-288th. 



C. (?) licusfidcdus. — Lorica ovate, compressed, the two points 

 posteriorly strong; toes short. Length l-288th. 



C. caudatus. — Lorica ovate^ compressed, posterior points distinct; toes 

 longer than the foot. The shell resembles C. uncinatus, but the toes are 

 much longer. Found both in fresh and sea water. Lorica l-288th. 



C. dcjli'xus. — Lorica ovate, compressed; the shell is more rounded, 

 and very transparent. Figs. 460 to 462 represent back^ under, and 

 side views ; the former shews the vesicles. Found in the clear 

 water of a peaty moor. Length 1 -240th. 



Genus Metopidia. The frontal-eyed Rotatoria have two eyes in 

 front, a furcate foot, and a depressed or prismatic lorica ; the frontal 

 portion naked or uncinate (not provided with a hood) ; indeed they 

 may be termed Lepadella, with two red frontal eyes ; the lorica ap- 

 pears to be closed on the under side ftestula.J In two species the 

 rotary organ has from three to four muscles, and in one species two 

 foot muscles are observed. Two species have a frontal hook (rcspi- 

 ratoiy tube), like Colurus. The esophageal head in one species has 

 two, in another four, but in the thii-d no distinct teeth ; a short 

 oesophagus, and two spherical glands, are present in all. Two species 

 have a distinct constricted stomach fgasterodela. J An ovarium is 

 present, and M. triptera has a contractile vesicle. 



M. hpadclla. — Loi-ka depressed, nearly Hat, broadly ovate, 



