94 FBESH-WATEK RHIZOPODS OF NORTH AMERICA. 



but, like the former, is devoid of the flagellum. Dactylosphserium is a 

 smaller animal than Dinamceba, of irregularly rounded form, and from 

 0.012 to 0.06 mm. in diameter. The pseudopods projecting in all directions 

 are somewhat conical and blunt. Two varieties are described, in one of 

 which the endosarc is occupied with multitudes of bright-yellow corpuscles; 

 in the other, with green corpuscles. In most examples of the variety with 

 green corpuscles, the body is covered with minute villi of protoplasm, 

 which, though simulating the minute spicules investing Dinamceba, are 

 clearly of a different character. 



HYALODISCUS. 



Greek, hualos, crystal ; discos, a quoit. 

 Hyalodiscus : Hertwig and Lesser, 1874. Plakopus : Schulze, 1875. 



Body naked, discoidal, consisting of a colored granular endosarc, with 

 nucleus and vacuoles, and a clear colorless ectosarc, which in motion of the 

 animal extends in a broad zone beyond the colored mass of endosarc, and 

 projects pointed conical processes mostly few in number. 



HYALODISCUS RUBICUNDUS. 



Plate XLV, figs. 17, 18. 



Hyalodiscus rubicundus. Hertwig and Lesser: Arch. mik. Anat. 1874, x, Supl. 49, Taf. ii, Fig. 5. 

 t Plakopus ruler. Schulze : Arch. mik. Auat. 1875, xi, 348, Taf. xix, Fig. 9-16. 



Endosarc brick-red in color. 

 Size. — 0.03-0.06 mm. diameter. 



In the outset of my studies of the Fresh- water Rhizopods, I met with 

 several specimens of what I suppose to be the curious colored amoeboid 

 form described by Hertwig and Lesser under the name of Hyalodiscus 

 rubicundus, but I have since seen no others. They were found in the 

 ooze of Cooper's Creek, New Jersey, in the month of May. 



One of the specimens, shortly after being noticed, exhibited the appear- 

 ance seen in fig. 17, pi. XLV. It had an irregularly circular outline, 

 measured about 0.0625 mm. in breadth, and consisted of two portions. 

 One of these was an orange or light brick-red body with a variable number 

 of conical pointed processes ; the other was a thin, delicate, broad, cres- 

 centic band of clear colorless ectosarc embracing more than half the cir- 

 cumference of the former. The animal slowly glided in an amoeba-like 

 manner, in the direction of the pseudopodal expansion of ectosarc. In its 



