1880.] NATURAL SCIENCES OF PHILADELPHIA, 15*1 



red Cyclops, becomiug, after a few clays, as a result of feeding- on 

 the latter, of the same orange-red hue. Subsequentl^y, when food 

 became scarce, the red Hj'dras lost their bright color. 



In one of the ponds, the stems of rushes and dead branches of 

 trees were invested with a bright grass-green stratum, consisting 

 of a bright green Vorticella, probably the V. fasciculafa of Midler. 

 The green color is dependent on chloroph^'l granules, as an 

 element of the structure, and not on food. The body of the 

 animal ranged from O'lOS mm. long by 0"Ofi mm. broad, to 0'12 

 mm. long by 0'09 mm. broad. A few measured were 0'1.5 mm. long 

 by 0*102 mm. broad at the peristome. In a large active bunch, 

 most of them measured 0-09 mm. long and broad. The pedicels 

 were from five to eioht times the length of the bodv. 



In another pond, the water was rendered turbid from the pro- 

 fusion of Volrox glohator. In a bay of this pond filled with dead 

 leaves, a portion of water taken into a jar appeared opalescent 

 from the quantity of minute white flakes it contained. These, on 

 examination, proved to be Spirostomum amhiguum. In the same 

 pond, the Spatterdock, Nuphar ad vena, was just about unfolding 

 its leaves, and mau}^ of these were thickly invested with a clear 

 jelly, dotted with bright green spots. These proved to be Sfentor 

 yjolymorphus. On the underside of a few open leaves on the sur- 

 face of the water, were many spots of bright green and dull red- 

 dish. The former consisted of groups of the green Vorticella 

 before mentioned, the other consisted of attached groups of a 

 lilac- or amethystine-colored Stent07\ probably S. igneus. Similar 

 groups of this Stenfor were observed on a floating log, which had 

 been in the water since last 3'ear, as it exhibited attached many 

 statoblasts of a Plumafella. Ehrenberg describes S. igneus as 

 bright yellow or vermilion ; Stein as blood red, or often lilac- 

 colored, or vermilion to brownish red. Ehrenberg found it at- 

 tached to Hottonia. Stein says he never saw it fixed, but alwaj'S 



swimmmg. 



The Woodbury variety which might be named S. amethystinus, 

 was abundant and invariably found in conspicuous groups, visible 

 to the unaided eye, and when detached, thougli the animals swam 

 about actively, they were not onl}' disposed to become fixed, but 

 they actualh^ gathered together in groups. They all contained an 

 abundance of chloropbyl, apparently derived from food, but the 

 exterior structure was invariably of a distinct amethystine hue, 

 dependent on fine molecules. The color was more pronounced in 

 the longitudinal bands approaching the peristome. The nucleus 

 was spherical. 



In the attached state, when the animal was fullj^ extended and 

 presented a trumpet shape, it was 0*6 mm. long by 0"18 mm. wide 

 at the peristome. This was a common size, but some measured 

 were O'Si mm. long. In the conical form, when swimming, indi- 

 viduals ranged from 0'2!r to 0-45 mm. long. In the most con- 



