130 FEESH-WATEE EHIZOPODS OP NOETH AMEEICA. 



The sarcode in the few specimens observed occupied about one half 

 of the interior capacity of the shell. It was inverted vase-like in shape, 

 attached at the border of the mouth, gradually contracting and then 

 expanding again within the body. It was attached by long diverging 

 threads of the ectosarc to the sides and fundus of the shell. 



The sarcode is colorless, and its basis consists of a pale, finely granular 

 protoplasm. Imbedded in the body, toward the fundus of the shell, it 

 contains a large, faintly granular and globular nucleus, from g^th to g^th 

 of an inch in diameter. At the periphery of the body, contiguous to the 

 nucleus, two or three contractile vesicles may be visible at once. 



Around, but especially below, the position of the nucleus, the endosarc 

 contained a midtitude of darkly outlined granules, and a variable number 

 of larger, clear, well-defined globules, oil-hke in appearance. A few pale 

 vacuoles and small brown food masses were likewise visible. 



Usually S. cuneata puts forth but a single digitate pseudopod, but 

 occasionally two and less rarely three are emitted. They present the com- 

 mon form and the scarcely perceptible granular character observed in 

 related animals. 



H. cuneata, from its great transparency, would be admirably adapted 

 for the study of the various life phenomena of its kind, but unfortunately 

 the creature appears to be exceedingly rare. In four years I found only 

 half a dozen individuals, and all these were obtained from the same locality, 

 a spring, in which grew water-cress, near Lansdowne station, on the West- 

 chester railway, a few miles from Philadelphia. 



In one instance two individuals were found in conjugation, and when 

 first observed they presented the appearance seen in fig. 6. The sarcode 

 of both was continuous at the mouth of the shells ; but in one of these it 

 was less than a fourth of the quantity in the other. A moment after, the sar- 

 code was observed to flow from the larger to the smaller portion until the 

 two became equal in size, and assumed each a trilobate form, as seen in 

 fig. 7. A fourth lobe was produced in one portion of the sarcode, and then 

 the lobes became extended in both so as to form an attachment to the sides 

 and fundus of the shell, as seen in fig. 8. Shortly after, one portion of the 

 sarcode narrowed its connection with the other at the mouth of the shell, 

 then detached itself and shrunk away, as represented in fig. 9. At this time 

 the specimens were accidentally lost ; but several hours later, one of the 



