274 



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 cUia. Body longitudinally or 

 spirally striated. . . . Lacrymaria Ehrenberg. 



Representative species. . iacrywaric o/or Miiller 1786. 



A common species foimd 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 ii. 

 Fig. 471. Lacrymaria olor. ci), contractile vacuole; «, nu- 

 cleus. Expanded. X so. (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 ji. 

 Pond water. 



34 (13) 



35 (48) 



36 (43) 



37 (42) 



38 (39) 



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

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



Body as3Tnmetrical with, dorsal side arched 35 



Mouth subterminal or terminalj body greatly elongated. 



36 



Mouth usually open, pharynx often rod-like 37 



Mouth subterminal 38 



Anterior end hook-Uke, bent to the left; elongated, flattened, leaf- 

 like. Ventral surface flat with ciliated ribs; dorsal surface 

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

 ing into a pharynx Loxodes Ehrenberg. 



Representative species. .... Loxodes rostrum MuUer 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 n. At the 



bottom of old infusions. 



Fig. 473. Loxodes roslrum. X 250. (After Conn.) 



39 (38) Anterior end not hook-like 40 



