72 FRESH-WATER RHIZOPODS OF NORTH AMERICA. 



nine acutely divergent, segmented filaments of variable length. A con- 

 tractile vesicle and a nucleus present. 



Size. — Ranging from 0.04 mm. long by 0.032 mm. broad to 0.076 mm. 

 long by 0.02 mm. broad; the caudal appendages from 0.012 mm. to 

 0.045 mm. long. 



Locality. — In the ooze of a broad spring, near Lansdowne station, on 

 the Westchester railroad, about five miles from Philadelphia. 



In association with Ouramceba vorax, at Lansdowne station spring, three 

 years in succession, I found what I have supposed to be a different and 

 smaller species, for which I have proposed the name heading the present 

 chapter. If Ouramceba be really a distinct genus from Amoeba, it is proba- 

 ble that the smaller form under consideration may be the young of Oura- 

 mceba vorax. 



Ouraiuceba botulicauda (figs. 13-17, pi. IX) ordinarily exhibits 

 an irregularly angulated outline, and often assumes a palmate shape with 

 short angular digit-like pseudopods. The ends of the latter present 

 variable proportions of clear ectosarc, and they move and retract more or 

 less in succession as the animal moves along. The posterior end of the 

 body is somewhat tapering and obtuse, and gives attachment to a variable 

 number of appendages. These form a single tuft divergent from a single 

 point; but occasionally there are two tufts. The appendages are commonly 

 three, but range up to nine. They are of variable length, straight, and 

 consist of series of elongated elliptical bodies, from one to four, also of 

 variable length. They resemble strings of sausages, whence the specific 

 name given to the animal. 



The endosarc of Ouramceba botulicauda is pale granular, mingled with 

 a few oil-like molecules. Generally the specimens observed of the animal 

 contained but little food in the form of balls. One individual contained a 

 single diatom. One or two contractile vesicles are usually present, as 

 seen in the figures. A distinct nucleus was also commonly present. 



PELOMYXA. 



Greek, pdos, nrail; muxa, mucus. 

 rcloMns: Greeff, 1870. Pelomyxa: Greeff, 1874. 



Animal with the general character of Amoeba, naked, of variable and 

 inconstant form, in the quiescent condition spheroidal or ovoidal, in motion 



