FRESH-WATER BIOLOGY 



31 (30) Long, ribbon-like; no proboscis. Mouth terminal with an evident 



pharynx. Nucleus in the posterior third of the body and a 



row of minute vacuoles near one side. . Flexiphyllum Conn. 



Representative species ..... Flexiphyllum elongatum Conn 1905. 



FIG. 470. Flexiphyllum elongatum. X 220. ' (After 

 Conn.) 



32 (29) Body not flattened; with a long, highly contractile neck; a plug- 



like projection carrying the terminal mouth which is sur- 

 rounded by a crown of long cilia. Body longitudinally or 



s spirally striated. . . Lacrymaria Ehrenberg. 



Representative species Lacrymaria olor Miiller 1786. 



A common species found in pond water. Its 

 swan-like appearance was suggested to the early 

 observers by its graceful movements, as it swims 

 about extending its neck here and there in search of 

 food. Length, neck contracted, 50 to 70 M- 

 FIG. 471. Lacrymaria olor. cv, contractile vacuole ;n, nu- 

 cleus. Expanded. X 50. (After Blochmann.) Con- 

 tracted. X 200. (After Conn.) 



33 (28) Body not elongated, spherical to ovate; anterior end not oblique. 



Mouth terminal or subterminal, pharynx usually with rods. 



Nucleus ovate to ribbon-like. . . . Prorodon Ehrenberg. 



Representative species Prorodon ovum Ehrenberg 1833, 



Body oval, evenly rounded at both ends; mouth eccentric, open- 

 ing into a conical pharynx which leads far into the body. Rods of 

 pharynx conspicuous. Cilia of posterior border longer. Nucleus 

 spherical, central. Contractile vacuole posterior. Length 125 /u. 

 Pond water. 



FIG. 472. Prorodon ovum, cv, contractile vacuole; macn, macro- 

 nucleus; mien, micronucleus. X 170. (After Blochmann.) 



34 (13) Body asymmetrical with dorsal side arched 35 



35 (48) Mouth subterminal or terminal, body greatly elongated. ... 36 



36 (43) Mouth usually open, pharynx often rod-like 37 



37 (42) Mouth subterminal 38 



38 (39) Anterior end hook-like, bent to the left; elongated, flattened, leaf- 



like. Ventral surface flat with ciliated ribs; dorsal surface 

 curved, without cilia. Mouth on the left anterior edge, lead- 

 ing into a pharynx Loxodes Ehrenberg. 



Representative species Loxodes rostrum Miiller 1786. 



The body of this species is highly vesicular. Nuclei 

 may be two or more. Wrzesniowski has demonstrated a 

 racemose system of nuclei. Length 250 to 400 . At the 

 bottom of old infusions. 



FIG. 473. Loxodes rostrum. X 250. (After Conn.) 



39 (38) Anterior end not hook-like 40 



