78 PROCEEDINGS OF THE ACADEMY OP 



The}^ are not used in securing food, nor is their function obvious. 

 The Ouramceba moves like an ordinary Amoeba, and obtains its 

 food in the same manner. The tail-like rays are not retractile, 

 and they are rigid and coarse compared with those of Actino- 

 phr3'ens. They are simple or unbranched, except at their origin, 

 and they are C3diiKlrical, of uniform breadth, and less uniform 

 length. When torn from the body they are observed to originate 

 from a common stock attached to a rounded eminence. 



Several forms of the Ouramceba were observed, but it is uncer- 

 tain whether they pertain to one or several species. One of the 

 forms had an oblong ovoid body about the |^th of a line long and 

 y^jth of a line broad. The tail-like rays formed half a dozen tufts, 

 measuring in length about the width of the body. The latter 

 was so gorged with large diatomes, such as Navicula viridis, 

 together with desmids and confervoe, that the existence of a 

 nucleus could not be ascertained. The species may be distin- 

 guished with the name of Ouramceba vorax. 



A second form, perhaps of a different species, moved actively 

 and extended its broad pseudopods like Amoeba, princeps. Wli^n 

 first viewed beneath the microscope it appeared irregularly globu- 

 lar and about the iV^'^ ^^ ^ ''" ^^^ diameter. It elongated to the 

 ^th of a line, and moved with its tail-like appendages in the rear. 

 These appendages formed five tufts about the ^V^^ ^^ ^ ^^" ^^ng. 

 The interior of the body exhibited a large contractile vesicle and 

 a discoid nucleus. This second form may be distinguished with 

 the name of Ouramceba lapsa. 



Another Ouramoeba had two comparatively short tufts of ra3'S, 

 and a fourth, of smaller size than the others, had a single tuft of 

 three moniliform rays. 



It is possible that Ouramoeba is the same as the Plagiophrys 

 of Claparede, though the description of this does not apply to 

 that. 



Plagiophrys is said to be an Actinophryen, furnished with a 

 bundle of rays emanating from a single point of the body, but 

 the rays are described as of the same kind and use as those of 

 Actinophrys. Plagiophrys is further stated to be provided with 

 a distinct tegument like Gorycia of Dujardin, or Pamphagus of 

 Baile}'^, but the body of Ouramceba is as free from any investment 

 as an ordinary Amceba, and the rays are fixed tail-like appen- 

 dages with no power of elongation or contraction. 



The species of Ouramoeba were found among desmids and dia- 

 tomes, on the surHice of the mud at the bottom of a pond, near 

 Darby Creek, on the Philadelphia and West Cliester Railroad. 



Two of the commonest species of Difflugia of our neighborhood 

 I had until recently confounded together as D. proleiformis, and, 

 perhaps, the two forms \x\a.y be included inider the latter name in 

 Europe. In one the mouth is deeply trilobed, and the animal is 

 usually green with chlorophyl globules. In the other the mouth 



