OF THE ROTATORIA. 481 



species Notoinmata Tigris and N. longiseta (Ehr.). Leydig surmises that 

 Microcodon is a male animal. 

 V. With a short foot ; the foot-processes equal to the foot in lengthy or but slightly 

 shorter or longer. 



Comprises the genera Hydatina, Pleurotrocha, Biglena, Batulus, Distemma, 

 Triophthalmus, Eosphora, Cycloglena, Theorus, Synchtefa (Ehr.), and 

 Lindia (Duj.); together with the species Notommata Ticba, N. petro- 

 myzon, N. saccigera, N. Copeus, N. centrura, N. brachyota, N. collaris, 

 N. Najas, N. aurita, N. gibba, N. ansata, N. decipiens, N. Felis, N. para- 

 sitica, N. tripus (Ehr.), N. tardigrada (Leydig), N. vermicularis (Duj.), 

 N. roseola and N. onisciformis (Perty), and the Furcularia Rheinhardtii 

 (Ehr.), which is, however, actually a Notommata. The genus Lindia 

 (Duj.) is doubtful ; and that of Enteroplea (Ehr.) is the male of Hyda- 

 tina senta. 

 yi. Without a foot. 



Is represented by the genus Albertia (Duj.). 



B. Figure saccular. 



I. With a short foot. 



Such are the species Notommata clavulata'^, N. Myrm^leo, N. Syrinx, and 

 Biglena lacustris. 

 II. Without a foot. 



Includes Notommata anglica (Dalrymple), N. Sieboldii (Leydig), Polyarthra 

 platyptera (Ehr.), and the genera Triarthra (Ehr.) and Ascomorpha 

 (Perty). 



C. Figure compressed. 



a. Compressed horizontally. 

 L With a foot. 



Represented by the genera Euchlanis, Lepadella, Monostyla, MetopidAa, 

 Stephanops, Squaniella, Noteus, Brachionus, Pterodina (Ehr.), and 

 Notogonia (Perty). 

 II. Without a foot. 



The genus AnurcBa (Ehr.). 



b. Compressed laterally. 

 Includes the genera Salpina, Mastigocerca, Monura, and Colurus (Ehr.). 



This arrangement of the Eotatoria the author confesses to be defective. 

 In our opinion, it has no advantage over the scheme of Dujardin, and, on 

 the other hand, wants its simplicity. Its basis is not such as will combine 

 the species according to their natural aflElnities ; for there is no necessary or 

 direct relation between external fonn and internal organization, and it is on 

 the latter alone than any classification can securely repose. 



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