496 



FRESH-WATER BIOLOGY 



48 (47) Striae resolvable into rows of dots, altered on lateral fields. 



Teratocephalus de Man. 



Interesting genus of few species, with movable cuticular lips. Species have thus far been 

 found only in fresh water and wet soils, but the genus appears to have a world-wide distribution, 

 at least in temperate regions. Teratocephalus seems related to Cephalobus from which, how- 

 ever, it differs strikingly in the formation of the lips and pharynx. It is difficult to determine 

 the functions of the movable cuticular labial elements (a). The most reasonable assumption 

 appears to be that they are biting organs. 



-.Representative species Teratocephalus cornutus Cobb 1914. 



i-vi iy/ QI 19 u" 



The cuticula is traversed by about 1500 transverse 

 striae, resolvable into rows of minute dots, which are 

 modified on the lateral fields. The movements of 

 which the lips are capable are plainly indicated in 

 Figs. II and IV. The relatively large eggs are ex- 

 tremely mobile, so that they pass out through the 

 relatively small vulva without difficulty. Contact 

 with water, however, appears to harden the shell so 

 that after deposition the eggs have a more definite 

 and rigid form. These phenomena are characteristic 

 of the eggs of many genera, especially those in which 

 the eggs are of relatively large size. In the present 

 species the eggs are deposited before segmentation 

 begins. The general form of the tail, and its termi- 

 nus, would seem to suggest the presence of caudal 

 glands, but none have been seen. 



The cardiac bulb so strongly developed in this 

 species is similar to that found in Rhabditis, Plectus, 

 Cephalobus, etc. It consists of three movable valves 

 rolling against each other, that can be pulled back- 

 ward by appropriate muscles. The arch over them 

 meanwhile remains rigid; thereby a vacuum (suction) 

 is produced. The minute striation on these valves 

 has suggested that they are triturating organs, but 

 the food habits would not seem to necessitate such 

 an assumption. It seems more likely that the 

 striations are due to such a disposal of the cuticula 

 as will give to the organs the necessary strength and 

 efficiency. These valves act rapidly, often several 

 times per second. 



Habitat: Maple River, Michigan. 



FIG. 799. Teratocephalus cornutus. 



I, lateral view of a female: II, lateral view of head, 

 more highly magnified; III, front view of head; IV, 

 dorso-ventral view showing lips wide open; V, cuticula 

 showing lateral field. 



a, one of the six movable, cuticular lips; b, one of 

 the four submedian cephalic setae; c, amphid; d, nerve- 

 ring; e, excretory pore; /, organ of unknown signifi- 

 cance; g, cardiac bulb; h, intestine; i, anus; j, rec- 

 tum; k, cuticula; /, one of the cells of the intestine; 

 m, lumen of the intestine; nn, flexures in ovary; o, egg; 

 p, vulva; q, blind end of posterior ovary; u, terminus. 

 (After Cobb.) 



49 (38) Esophagus without bulbs . 



50 (57) Pharynx none 



51 (56) Caudal glands and cephalic setae present. 



52 



