. Fresh-water biology. Freshwater biology. THE FREE-LIVING FLATWORMS (TURBELLARIA) 349 62 (63) Genital pore in posterior third of body. . Tribe Olisthanellini Excretory system opens on fdorsal surface with one asymmetrical or two symmetrically placed openings. Testes dorsal to the yolk glands. Without atrial copulatory organ. Single genus thus far reported in America Olisthanella. Only one species in this country. Olisthanella caeca (Silliman) 1885. Length mm. Without eyes. Without long sensory hairs. Color grayish-white. Sometimes apparently colored, due to food in intes- tine. Pharynx ro
. Fresh-water biology. Freshwater biology. THE FREE-LIVING FLATWORMS (TURBELLARIA) 349 62 (63) Genital pore in posterior third of body. . Tribe Olisthanellini Excretory system opens on fdorsal surface with one asymmetrical or two symmetrically placed openings. Testes dorsal to the yolk glands. Without atrial copulatory organ. Single genus thus far reported in America Olisthanella. Only one species in this country. Olisthanella caeca (Silliman) 1885. Length mm. Without eyes. Without long sensory hairs. Color grayish-white. Sometimes apparently colored, due to food in intes- tine. Pharynx rosette-shaped and nearly central in position. Intes- tine large. Rhabdites and tracts prominent. Female organs only are known. Sluggish and found only in mud under stones. Monrce Co., N. Y. Fig. 619. Olisthanella caeca, ph, pharynx; i, intestine; b, brain; wi, yolk gland; oi), ovary; go, genital pore; /i, rbabdite tracts. X 35. (After Silliman.). 63 (62) Genital pore in anterior two-thirds 64 64 (71) Testes ventral to the yolk glands. Rhabdites only in mesenchyma tracts Tribe Typhloplanini . 65 Protonephridia with two main branches which communicate with the exterior through a transverse branch which leads either to the mouth or to the genital atrium. With or without atrial copulatory organs. 65 (66) Anterior end of body a retractile proboscis. . Rhynchomesostoma. Only one species. . Rhynchomesostoma rostratum (MiiUer) 1773. Length 2 mm. European specimens reach a length of s mm. when extended. Very transparent. Body fluid rose or yellowish-red in color. Intestine contains B yellowish-red oil droplets. Ventral surface flat, dorsal convex. Anterior end of body like a telescopic tube. Pharynx small, lying somewhat before the middle of the body. Rochester, N. Y. Fig. 620. Rhynchomesostoma rostratum. {A) Proboscis partly extended. (S) Fully contracted. X 40. (After von Graff.). Please note that these images are extracted from scanned page images that may have been digitally enhanced
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
