THE FREE-LIVING FLATWORMS (TURBELLARIA) 



359 



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end. Eye spots elongated, crescentic, facing outward and forward at an angle of 43° to the 



chief axis of the worm. Intestine of the simple triclad 

 type; no fusion or anastomoses of posterior stems. 



This description is from a single immature alcohohc 

 specimen. (It is quite possible that the apparent lack 

 of cephalic appendages is due to the effect of the killing 

 fluid.) Collected off N. Y. Point, Lake Mich. 



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Fig. 637. Planaria simplex. From preserved material. 

 X 10. (After Woodworth.) 



101(84) Without eyes Planaria fuliginosus Leidy 1&51. 



Length about 5 mm., breadth 4 mm. Body oval, dilated; interiorly flat, superiorly mod- 

 erately convex, fuliginous. Eyes none; in their ordinary position a slightly greater accu- 

 mulation of black pigment upon the upper surface. Mouth a little posterior to the center- 

 Esophagus simple. Rancocas Creek near Pemberton, New Jersey. 



102 (83) Normal eyes many, arranged so as to suggest a coronet near 



the margin of truncated head and extending back near 

 the lateral margins to a somewhat variable distance. 



Folycelis. 

 Only one species known in this country. 



Polycelis coronata (Girard) 1891. 



Length 8 mm., breadth 2 mm. Color fuliginous or sooty, uniform, somewhat darker on the 

 median dorsal region than on margins. Elongated lanceolate. Anterior margin truncated, 

 weakly bilobed or undulating. The numerous eyes are arranged as a coronet or as an arc of 

 a circle, the arrangement being dependent to some extent 

 on size. Pharynx elongated, central. Collected near Fort 

 Bridger, Wyoming. It is quite possible, as Hallez notes, that 

 this is a synonym of the European Polycelis nigra. 



Fig. 638. Polycelis coronata. From life. X 5. (After Girard.) 



103 (80) Pharynges numerous. Phagocata. 



Only one species known in this country. 



Phagocata gracilis (Haldeman) 1840. 



This species was found and recorded by Haldeman; it was first adequately described by 

 Leidy to whom it is ordinarily attributed. 



Largest specimens 35 mm. long, 4.5 mm. wide. Color shiny black by reflected light, green- 

 ish-gray by transmitted hght. Varies from black to a reddish-brown on one hand or to a light 

 gray on the other. Small specimens at times almost milky-white. Ventral side lighter than 

 dorsal. Lateral margins nearly parallel. Widest through pharyngeal region. Anteriorly 

 sides converge slightly up to about the region of eyes where the diameter increases to form the 

 head with its rounded cephalic appendages. Posteriorly sides converge to a point. Eyes 

 two with elongated circum-ocular areas. The numerous pharyngeal tubes lie in a common 

 chamber and open separately into the intestinal tract. When extruded they reach the exterior 

 through a single orifice. Pools and rivulets, Mass., Penn., Ohio, Wis. 



Fig. 639. Phagocata gracilis. (^) Living animal extended, X 4. (5) Partial reconstruction to show 

 pharynges and their relation to the intestinal tract. X about 8. (After Woodworth.) 



104 (79) Found in moist places on land. . . Suborder Terricola . . 105 



The so-called land planarians are forms which in a biological sense stand very near the 

 water-living species. They occur only in very moist localities and under circumstances may 

 be taken for fresh-water forms. In general appearance they resemble minute, deUcate slugs. 

 When examined under the microscope the structure appears clearly to be that of a flatworm 

 rather than of a moUusk. The few known species are widely and sparsely distributed. They 



