THE FREE-LIVING FLATWORMS (TURBELLARIA) 



347 



57 (58) Terminal spine of only one cerminal branch unlike the others in 

 shape Dalyellia rossi von Graff 191 1. 



Length a little over i mm. Similar in form to D. rheesi. Color of 

 mesenchyma bright or dark reddish-yellow to cinnamon-brown. Eyes 

 brown or black. Intestine brownish-yellow. Adhesive cells on short 

 tail. Common at Rochester, N. Y. In brackish water, Falmouth, Mass. 

 See Fig. 589 for view of entire animal. 



FIG. 615. Dalyellia rossi. Chitinous part of male copulatory organs, st, chitin- 

 ous stalk; eai and ea-i, terminal branches with spines; mv and md, median ventral and 

 dorsal projections. X 285. (After von Graff.) 



58 (57) Terminal spines on both terminal branches unlike the others in shape. 



Dalyellia sillimani von Graff 1911. 



Length i mm. Integument colorless with small rhabdites. In heavily pigmented speci- 

 mens the mesenchyma appears dark brown; those with less pigment show cells filled with yellow 

 fluid and containing brown pigment granules. Intestine ocher-yellow. Eyes black. Roches- 

 ter, N. Y., in brooks and pools. 



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FIG. 616. Dalyellia sillimani. (A) slightly compressed: bs, bursa seminalis; e, egg; ov, ovary; go, 

 sexual pore; vs, vesicula seminalis. X 70. (B) Male copulatory organ: ea v and eo?, terminal branches of 

 chitinous organ; kdr, granular glands of one side; ks, granular secretion; md, median dorsal chitinous 

 point; mp, retractor muscles; mv, median ventral grooved chitinous piece; pit, cirrus opening; vd, vas de- 

 ferens; vs, vesicula seminalis; s jf last chitinous plate of right terminal branch; sp, last chitinous plate of 

 left terminal branch; st, stalk. X 330. (After von Graff.) 



