626 



DESCRIPTION OF 



[Rotatoria. 



shaped glands, and a contractile vesicle. The egg is worthy of 

 notice, having sometimes a smooth soft shell, at others a hard 

 spinous one ; the latter is termed the winter ovum, and considered 

 by M. Turpiu as constituting the genera Bursellaand Erithrinella (?) 

 of plants. In eleven genera, a vascular system, composed of 

 transverse and longitudinal vessels, a cervical net-work and free 

 tremulous organs, like gills, with respiratory tubes or openings in 

 the neck, are observed. The system of sensation is indicated by 

 the presence of eyes, mostly red, with a ganglion beneath them ; 

 these organs, seated anteriorly upon the edge of the upper surface 

 of the body, or in the neck opposite to the mouth, indicate the 

 back or dorsal surface of the animalcule. Nerve-like fibrillse 

 also exist in several species of Notommatn, Bigleiia, Enteroplea, 

 Triai'thra, and especially in Ilyclatina. Some species of Synchaeta 

 evolve light and give rise to the phosphorescence of the sea. 

 Hydatina senta, Diglena catellina, and Triarthra, ai*e sometimes so 

 numerous as to render the pools of water in which they reside 

 milky and turbid. 



The jrenera are related as follow : — 



Ttceth absent Enteroplea 



Eyes \ 

 absent 



teeth present I 



r 



Eyes 

 present 



jaw many-toothed Hydatina. 



jaw single-toothed Pleurolrocha. 



rfrontal , Furcularia. 



foot styliforra Monocerca. 



L'r\ ical 



foot 

 furcated 



{front cilia, no unciui or styles .... Notommata. 



frontal cUia and styles Synehaeta. 



frontal cUia and uncini Scaridiunj. 



Lno foot, but a many partile beard, or fins .... Polyarthra. 



r foot furcated Diglena. 



frontal J r ^ r beard Ti-iarthra. 



[ styliform | ,^^ ,^^.^j. j Battulus. 



l^ccnical ; foot furcated Distemma. 



r , cervical Triophthalmus. 



J pedicelled -^ ^^,^ frontal, one cervical Eosphora. 



two pedicelled frontal eyes, one non-pedicelled cervicall otoo-lcna 

 V. eye ■• " 



with many simply conglomerate eyes, more than tliree Cycloglena. 



>wwith many doubly-conglomerate eyes, more than three Theorus. 



