. Fresh-water biology. Freshwater biology. 3 so FRESH-WATER BIOLOGY 68 (69) With a separate receptaaJum seminis, whose short duct is closed by a muscular ring. Dermal rhabdites present. . Strongylostoma. Only one species known in this country. Strongylostoma gonocephalum (SUliman) 1885. Length i-2 mm. Mesenchyma yellowisli, intestine with yellowish oil droplets. Eyes carmine red. Small rhabdites are present. This form differs from the widely distributed European form, Strongylostoma radiatum Miiller chiefly in the possession of two shallow oval pits which lie close behind the eyes at the side.
. Fresh-water biology. Freshwater biology. 3 so FRESH-WATER BIOLOGY 68 (69) With a separate receptaaJum seminis, whose short duct is closed by a muscular ring. Dermal rhabdites present. . Strongylostoma. Only one species known in this country. Strongylostoma gonocephalum (SUliman) 1885. Length i-2 mm. Mesenchyma yellowisli, intestine with yellowish oil droplets. Eyes carmine red. Small rhabdites are present. This form differs from the widely distributed European form, Strongylostoma radiatum Miiller chiefly in the possession of two shallow oval pits which lie close behind the eyes at the side. The integument is sUghtly raised around them and each bears vacuoles and rhabdoids. Excretory pore opens into mouth. Erie Canal, Monroe Co., N. Y. Fig. 621. Strongylostoma gonocephalum. {A) Entire animal: tr, tracts of rhabdites: M. pharynx; o», ovary; bs, bursa seminalis; vi, yolk glands; f, cirrus; go, genital pore; ec, egg capsule. X 40. (After Silliman.) (5) Out- line of anterior end with eye (a«) and shallow pit {sfi of one side. Enlarged. (After von Grafi.). 69 (68) Without a separate receptaculum seminis Typhloplana. Only one species known in this country. Typhloplana viridata (Abildgaard) 1790. Length to i mm. Transparent. Zoochlorellae in the mesenchyma give it a grass-green color. Tapering at both ends. Without eyes. Anterior end bluntly pointed, posterior end pointed. Pharynx just anterior to center. Sexual pore close behind pharynx. Viviparous. The summer eggs develop within the body of the parent. Winter eggs are as many as ten in number and yellowish-brown in color. The pear-shaped bulbous cirrus contains a straight chitinous tube, the ductus ejaculatorius. The male genital canal is set with small spines; the small egg-shaped or somewhat elongated testes lie near or back of the pharynx Luther and von Graff regard the form collected from Monroe Co., N. Y., and described by SiUiman luider the name of Mesostoma vimparum, also those collected from West Twin Lak
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
