PLATE III. 



A3KEBA VERRUCOSA. 



Figs. 1-4. Abundant form among' Oscillaria, in a bog at the foot of the Zoological Garden on the 

 Schuylkill River, Philadelphia, June, 1878. Mostly the animals contained an abundance of the alga 

 Lyngbya, many of the segriients of which were changed to brown as a result of digestion. 166 diameters. 



Fig. 1. Individual with much wrinkled ectosarc ending in a posterior minutely papillose extremity. 

 It exhibited three persistent longitudinal linen. The endosarc contains a discoid nucleus and two con- 

 tractile vesicles. The latter united before collapse and three afterwards appeared in the same position. 



Fig.-'. An individual nearly like the former, but exhibiting no longitudinal lines. 



FlG. 3. An individual with four Inngil uilinal lines, a small nucleus, and huge contractile vesicle. 



Fig. 4. An individual which when first observed looked nearly like the former, but which subse- 

 quently discharged the large pouch-like drop of yellowish liquid and brown-colored segments of Lyng- 

 bya. Many of the latter were at first green, and the surrounding liquid when within the body of the 

 animal also imparted a greenish hue. 



FIGS. 5-7. Forms, in water, squeezed from muss growing in the crevices of the brick pavement of 

 my house in Philadelphia; found in association with the Wheel-animalcule, Rotifer vulgaris, June, 1874. 

 333 diameters. 



FlG. . r >. Individual comparatively quiescent, with nucleus and contractile vesicle. 



Fig. 6. Individual with nucleus and food, but the contractile vesicle collapsed or absent. 



Fig. 7. Individual with nucleus, two contractile vesicles, and food-balls. . 



FlG.8. Small individual. It moved quickly with thetbroad end forward. Several contractile 

 vesicles would appear, conjoin in a single one and then collapse. Frequent form in the bog at the foot 

 of the Zoological i iarden, Philadelphia, June, 1878. 



Fig. 9. Small individual with active movement. It exhibits five contractile vesicles which all 

 conjoined in one before collapse. 5011 diameters. Frequent in bog-water, Broad Mountain, Schuylkill 

 ( lountj . Pennsylvania. 



Fig. 10. An individual widely spread and exceedingly sluggish in movement; with a nucleus and 

 contractile vesicle. 66b" diameters. 



Fig. 11. The same individual, magnified half the extent of the former, as observed swimming. 

 From the pavement at the fountain in front of the City Hall, on Market street, Philadelphia. 



Fig. 12. Individual with three longitudinal lines. It contains a nucleus, two contractile vesicles, 

 together with fragments of Lyngbya, and a diatom. 333 diameters. Fountain in Fairmount Park, 

 September, 1876. 



FlG. 13. An individual with four longitudinal lines. It shows two contractile vesicles, of which 

 the larger is in the act of collapse. With tin 1 preceding. 333 diameters. 



FlG. 14. An individual with live or six longitudinal lines. The contractile vesicle in the act of 

 collapse. 500 diameters. With the preceding. 



Figs. 15, 16. Two views of an individual, with four longitudinal lines. A variable number of 

 small contractile vesicles would appear as seen in fig. 15, conjoin as in fig. 16, then expand to a regular 

 sphere and collapse. Fort Bridger, Wyoming Territory, August, 1877. 



Fig. 17. Individual with two longitudinal lines. The contractile vesicle nearly collapsed. Same 

 locality. 



FlG. 18. Individual with four longitudinal lines. It contains a nucleus, many clear vacuoles 

 (inadvertently colored by the lithographer), and at the posterior extremity a large contractile vesicle. 

 Common in Swarthmore. brick-pond. 



FIGS. 19-27. Young forms, observed among green algous material, Lyngbya, etc., scraped from 

 the brick pavements in damp shaded places in Philadelphia, and preserved a lew days in a dish with 

 water. Small actively moving individuals, exhibiting mostly two to four longitudinal lines or folds, 

 containing a nucleus and a large posterior contractile vesicle. 500 diameters. 



Fig. 2S. Mature form, found with the preceding. 5D0 diameters. 



Fig. 29. Mature form. Found in association with those of tigs. 5-7. 333 diameters. 



Fig. 30, Individual containing a nucleus, contractile vesicles, and food consisting of yellowish 

 and colorless granular balls, a diatom, and grains of sand. 500 diameters. Marsh of the Uinta Mount- 

 ains, Wyoming Territory, August, 1877. 



Fig. 31. Individual, with nucleus, and large contractile vesicle (to left of the middle). The food- 

 contents consist of abundance of the alga Lj ngbya. The large posterior vacuole, with the greenish liquid 

 and numerous isolated segments of Lyngbya, was observed to be expelled. 500 diameters. Among the 

 algous slime at the base of tin -fountain, Eleventh street near Chestnut street, Philadelphia, September, 1876. 



Fig. 32. Individual, from among Oscillaria and other alga' preserved during the winter, obsi i veil 

 with others of same character, February. 1875. 



Fig. 33. Individual of sluggish habit, with discoid nucleus, contractile vesicle, and food-balls. 

 200 diameters. Swarthmore brick-pond. 



FlG. 34. Individual of exceedingly sluggish habit. With large discoid nucleus, contractile 

 vesicle, and food-balls. 500 diameters. Sphagnous swamp of Yineland.New Jersey, September, 1876. 

 The contractile vesicle from its first appearance to its greatest expansion required about ten minutes; 

 its collapse, about six seconds. 



FlG. 35. An almost motionless individual, without conspicuous contents except the contractile 

 vesicle, which was observed to collapse and reappear. 500 diameters. Fort Bridger, Wyoming Terri- 

 tory, August, 1877. 



Fig.36. Individual, with oval nucleus, contractile vesicle (to the right), and food-balls (errone- 

 ously colored). 200 diameters. From ooze on the rocks below Fairmount, Philadelphia, October, 1875. 



FlG. 37. Small active individual, found with the preceding. 



FlG. 38. Large sluggish individual, found with that of fig. 34. Besides the oval nucleus, and largo 

 contractile vesicle, it contained a Diffiugia constricta and a Trinenux encheltjs. 500 +. 



