GENUS &G YRIA . 755 



in a minute spine ; the left valve with a less developed crest and a posterior 

 spine only; pharyngeal tube simple, slightly curved. Length of body 

 1-250". HAB. Saltwater: Norwegian coast. 



This species corresponds with the Dysteria aculeata of Claparede and 

 Lachmann. 



Cypridium crassipes, C. & L. sp. 



Valves of carapace elliptical, widest posteriorly, united throughout the 

 posterior half of their dorsal surfaces ; both equally and entirely smooth ; 

 the caudal style very thick, its proximal extremity hollow, its distal one 

 sharply pointed ; pharyngeal tube simple, short, and straight ; contractile 

 vesicles two in number; endoplast spherical, subcentral. Dimensions 

 unrecorded. HAB. Salt water. 



Identical with the Dysteria crassipes of Claparede and Lachmann. 



GENUS IV. ^GYRIA, C. & L. 



Animalcules free-swimming, encuirassed, oblong, more or less bilaterally 

 compressed, valves of carapace two in number, united throughout the 

 dorsal border. A movable tail-like style projecting from the posterior ex- 

 tremity of the ventral groove. Pharyngeal armature consisting of a simple 

 horny tube. Inhabiting salt and fresh water. 



The more extensive coalescence of the valves of the carapace upon their 

 dorsal border serves to distinguish this genus from the preceding one. Many of its 

 members have been described, in the first place by Dujardin and subsequently 

 by Stein, under the generic name of Ervilia ; but as this title has been previously 

 employed by Turton in the year 1822 for a genus of the Mollusca, and also by Link 

 for a genus of leguminous plants, the one of sEgyria, proposed as a substitute by 

 Claparede and Lachmann, is here retained. 



.flQgyria monostyla, Ehr. sp. PL. XLII. FIGS. 35 AND 36. 



Valves of carapace elongate-rectangular, rather wider posteriorly, with 

 rounded corners, about twice as long as broad, the left valve having a 

 raised longitudinal border along the dorsal margin ; endoplast ovate, sub- 

 central ; contractile vesicles two or three in number. Length of body 

 1-300". HAB Salt water. 



This species is described by Stein under the name of Ervilia monostyla, it being 

 regarded by him as identical with the Euplotes monostyla of Ehrenberg and the 

 Ervilia legumen of Dujardin. In Claparede and Lachmann's work it takes its 

 place under the generic title here retained, as ^Egyria legumen ; since, however, its 

 identity with Ehrenberg's type is considered proved, the specific title first conferred 

 upon it by that earlier authority must necessarily take the precedence. 



.ffigyria angustata, C. & L. PL. XXII. FIGS. 39 AND 40. 



Valves of carapace irregularly ovate, the left valve convex, the right 

 one plane, abruptly narrowed and obliquely truncate anteriorly, the width 

 immediately following this narrower anterior portion nearly equal to the 



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