384 Miscellaneous. 



with tufts of tail-like appendages or rays, from which he proposed 

 to name the genus Ouramoeba. 



The rays project from what may be regarded as the back part of 

 the body, as the animal always moves or progresses in advance of 

 the position of those appendages. The rays are quite different from 

 pseudopods, or the delicate rays of the Actinophryens ; they are 

 not used in securing food, nor is their function obvious. The Our- 

 amoeba 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 Actinophryeus. They are 

 simple or unb ranched, except at their origin, and they are cylindrical, 

 of uuiform 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 Ouramoeba were observed ; but it is uncertain 

 whether they pertain to one or to soveral species. One of the forms 

 had an oblong ovoid body about g of a line long and -J^ 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 diatoms (such as Navkula viridis), together with desmids 

 and conferva?, that tbe existence of a nucleus could not be ascertained. 

 The species may be distinguished by the name of Ouramoeba 

 vorax. 



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

 extended its broad pseudopods like Amoeba princeps. When first 

 viewed beneath the microscope it appeared irregularly globular, and 

 about -Jj of a line in diameter ; it elongated to ^ of a fine, and 

 moved with its tail-like appendages in the rear. These appendages 

 formed five tufts about A- of a line long. The interior of the body 

 exhibited a large contractile vehicle and a discoid nucleus. This 

 second form may be distinguished by the name of Ouramoeba 

 lapsa. 



Another Ouramoeba had two comparatively short tufts of rays ; 

 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 

 Claparedc, though the description of the latter does not apply to it. 

 Plagiophrys is said to be an Actinophryen, furuished 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 Corycia of Dujardin or Pamphagus of Bailey ; but the body of 

 Ouramoeba is as free from any investment as an ordinary Amoeba, 

 and the rays are fixed tail-like appendages, with no power of elonga- 

 tion or contraction. 



The species of Ouramoeba were found among desmids and diatoms, 

 on the surface of the mud at the bottom of a pond, near Darby 

 Creek, on the Philadelphia and West-Chester Railroad. 



Two of the commonest species of Difflugia of our neighbourhood 

 I had until recently confounded together as D. proteiformis ; and 



