250 FRESH-WATER RHIZOPODS OF NORTH AMERICA. 



pointed at both ends. They resembled the simple spicules of the fresh- 

 water sponges. The pseudopodal rays were numerous, simple, and long, 

 like those of Actinophrys sol. 



Another Heliozoan, related with the preceding, is represented in fig. 

 3, and was found in the material adherent to a stone, on which grew 

 a Spongilla, from the Schuylkill River, at Philadelphia, The animal was 

 entirely colorless. The spherical body, composed of pale granular proto- 

 plasm, contained a central nucleus, and numerous scattered, clear globules. 

 Externally it was invested with a thick layer of protoplasm densely per- 

 vaded with delicate, curved spicules, arranged tangentially to the body, and 

 rising in pointed processes upon the pseudoj)odal rays. This creature 

 resembles the Raphidiophrys pallida of Schulze,* and probably pertains to 

 the same species. 



RAPHIDIOPHRYS ELEGANS. 



Plate XLII. 



t Actinophrys oculata and Actinophrys Sol. Carter: An. Mag. Nat. Hist, xv, 1865, 277, pi. xii, figs. 1-3. 

 Baphidiophrys elegans. Hertwig and Lesser : Arch. mik. Anat. x, 1874, Suppl. 218, Taf. iv, Fig. 1. — Leidy : 

 Pr. Ac. Nat. Sc. Phila. 1874, 167.— Archer : Quart. Jour. Mic. Sc. 1876, 374, pi. xxii, fig. 19. 

 Sphwrastrum conglobatum. Greeft': Arch. mik. Anat. xi, 1875, 29, Taf. ii, Fig. 24-26. 

 t Schalenlose Siisswasaor-Jiadiolarien. Focke : Zeitschr. f. wissens. Zoologie, 1888, 353, Taf. xxv, Fig. 1. 



Animal single, or usually in groups up to two or three dozen or more, 

 separated by more or less wide intervals, and united by narrow bands or 

 isthmuses. Individuals with the body more or less bright green from the 

 presence of chlorophyl corpuscles, or colorless when the latter are absent. 

 Spicules of the exterior protoplasmic envelope delicate, in the form of 

 semicircles, and tangentially arranged, with their convexity directed toward 

 the body and pseudopodal rays 



Size. — Diameter of the body 0.032 mm. to 0.04 mm.; length of pseu- 

 dopodal rays to 0.24 mm. ; length of the semicircular spicules 0.006 mm. 



Locality. — In springs and ponds among aquatic plants. Pennsylvania 

 and New Jersey. 



Ragthldiopltrys efiegans, represented in pi. XLII, occasionally 

 solitary, is commonly observed in groups of from five to twenty or more, 

 and on one occasion I found an assemblage of thirty-eight individuals 

 This remarkable creature, as usually seen, roaming about in flocks, appears 



* Archiv f. mik. Anatomic, x, 1874, 377, Taf. xxvi, Fig. 1. 



