396 DESCRIPTION OF [ftotataria. 



in different states of extension or contraction. Fig. 473 

 shews the eggs. Found in bog water and infusions of oak 

 bark. Length l-72nd. 



Genus CLXXIX. HYDRIAS. The Water-turner is 

 African, and characterized by its being devoid of eyes, 

 proboscis, and little horn-like processes at the foot ; the 

 two small rotatory organs, or wheels, being supported on 

 pedicles or arms. An cesophagal head, and an ovarium, 

 with a large ovum, has been seen by Ehrenberg. The 

 form is like a naked Pterodina. 



689. HYDRIAS cornigera. The Lybian Hydrias. 

 Body ovate, hyaline ; foot attenuated, resembling a furcate 

 tail. Fig. 474 represents an animalcule extended. Found 

 with oscillatoria, in standing water, from a small spring by 

 Siwa, in the Oasis of Jupiter Ammon. Length 1-1 90th. 



Genus CLXXX. TYPHLINA. The blind Vibrator, 

 like the last, has an African locality ; it is characterized by 

 absence of eyes, proboscis, and horn-like processes at the 

 base of the foot; its little wheels are sessile. It resembles 

 a very small Rotifer, without frontal proboscis or eyes. 



690. TYPHLINA viridis. The green Typhlina. Body 

 oblongo-conical, small: it is represented at group 475. 

 Found by Drs. Hemprich and Ehrenberg in a pool near 

 Cairo in Egypt, in such numbers as to colour the water 

 green. Length 1 -720th. 



Genus CLXXXI. ROTIFER. The proboscised Rotatoria 

 have two eyes, placed upon the frontal proboscis ; the foot 

 provided with little horn-like processes, and the two toes 

 bisulcated at their apices. A double rotatory organ (con- 

 sidered by Cuvier, and others, as a respiratory apparatus), 

 furnished with muscles, is seen in all the species ; also 



