. Fresh-water biology. Freshwater biology. 496 FRESH-WATER BIOLOGY 48 (47) Striae resolvable into rows of dots, altered on lateral fields. Teratocephalus de Man. Interesting genus of tew 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).

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. Fresh-water biology. Freshwater biology. 496 FRESH-WATER BIOLOGY 48 (47) Striae resolvable into rows of dots, altered on lateral fields. Teratocephalus de Man. Interesting genus of tew 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. !=• 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 foimd in Rhabditist 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 necessit

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