THE FREE-LIVING FLATWORMS (TURBELLARIA) 



341 



3S (36) The chitinous portion of the male copulatory organ is represented 

 merely by the chitinous tube of the ductus ejaculatorius. 



Dalyellia inermis von Graff 191 1. 



Length 0.6 mm. Flattened. Posterior end 

 modified into a Icind of adhesive dislc. Color 

 white by reflected light. Intestine very 

 broad and yellow in color. Eyes dull yellow. 

 Accessory pigment spots irregularly grouped 

 near the eyes. The locomotor movements 

 are very quick. Rochester, N. Y. 



Fig. 604. Dalyellia inermis. (^) Ventral view, 

 slightly compressed: e, eye; m, mouth; w, yolk 

 gland; ov, ovary; go, genital pore; co, male 

 copulatory organ; te, testes. X iis. (.B) Ad- 

 hesive disk of posterior end. (C) Male copula- 

 tory organ enlarged: ch, chitinous tube; ks, vesi- 

 cula granulorum; vs vesicula seminahs. X 300. 

 (After von Graff.) 



36 (35) Provided with true chitinous organ 37 



37 (38) Chitinous portion of cirrus consists of a single chitinous spine. 



Dalyellia rochesteriana von Graff 19 11 



Scarcely i mm. long. Closely resembles O. rheesi. Colorless, transparent 

 with very small dermal rhabdites. Brownish mesenchymatous pigment not 

 so abundant as in D. rheesi. Intestine reddish-ocher-yellow. Sexual pore 

 lies just posterior to the intestine in the beginning of the last third of the 

 body. Rochester, N. Y. 



Fig. 60s. Dalyellia rochesteriana. Male copulatory organ enlarged: ch, chitinous 

 spine; vs, vesicula seminalis; ks, vesicula granulorum. (After von Graff.) 



38 (37) Chitinous portion of cirrus consists of more than one piece. 



39 



39 (44) Chitinous portion of cirrus consists of a number of transverse spines 

 arranged in a row 40 



