. Fresh-water rhizopods of North America. Rhizopoda; Freshwater animals. 144 FEBSH-WATEE EHIZOPODS OP NOETH AMEEICA,. Opposite sides of the same shell. Besides figs. 20-25, pi. XXIV, the accompanying figures, in the arrangement of the plates of the shell, represent the more important varieties which I have observed. The size of the shell ranges from about the 355th to the ith of an inch in length by ^^th to j^^th of an inch broad. The sarcode is colorless, and in all its characters resembles that of Hy alosphenia. The food-vacuoles often appear yellowish. The nu- cleus when visible measures ab
. Fresh-water rhizopods of North America. Rhizopoda; Freshwater animals. 144 FEBSH-WATEE EHIZOPODS OP NOETH AMEEICA,. Opposite sides of the same shell. Besides figs. 20-25, pi. XXIV, the accompanying figures, in the arrangement of the plates of the shell, represent the more important varieties which I have observed. The size of the shell ranges from about the 355th to the ith of an inch in length by ^^th to j^^th of an inch broad. The sarcode is colorless, and in all its characters resembles that of Hy alosphenia. The food-vacuoles often appear yellowish. The nu- cleus when visible measures about the Ti-„th of an inch or more. The pseudopods are digitate and usu- ally two or three in number. In several instances I have found specimens, late in the season, with the sarcode in a quiescent or encysted condition. Fig. 25 represents such a specimen obtained from sphagnum in November. It was of the largest size, about the j^th of an inch in length. The plates were arranged ob- liquely across the shell, and were pretty uniform in size. The neck was occupied by a laminated diaphragm as thick as one third the length of the shell. The sarcode mass formed a compressed oval ball occupying a cen- tral position in the body of the latter The ball was nearly colorless or faintly yellowish, and granular, and contained several large oil-like glob- ules. A central clearer space appeared to indicate the presence of a nucleus. Dead shells are sometimes found containing in the interior a number of scattered plates, or the same in one or more little packets, like those composing the wall of the shell. Quad/rula symmetrica was first described by Dr. Wallich, under the name of Difflugia symmetrica, from specimens found in England. It was more recently described, and referred to a new genus, by Prof. Schulze, from specimens found near Dresden. Ehrenberg described the same as pertaining to three different species, under the names oi Difflugia assulata, D. carolinensis, and D. leptolepis. Th
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectrhizopo, bookyear1879
