256 



Explanation of Plate IV. 



Fig. I. Stichostemma grandis n. sp. A large individual, sketched 

 from life, magnified 2 diameters. For the sake of facilitating re- 

 production, alterations were made in the original coloured draw- 

 ing in representing red by black and yellow by white. 



Fig. 2 Head region of a young animal about 4 mm. long. Greatly 

 enlarged, e.g., cephalic groove; d. g., dorsal ganglion; m. c., 

 marginal constrictions behind the brain ; r. s., rhycho-stomodaeal 

 opening. 



Fig. 3. Anterior parts of a frontal section of head. c. c, pyloric 

 caeca; e.g., cephalic groove; c. n., cephalic nephridia ; pb., 

 proboscis (partly protruded); v.g., ventral ganglion. Magnified 

 about go diameters. 



Fig. 4. Cross-section through the middle region of a small but al- 

 ready mature individual about 10 mm. long. d. v., dorsal vessel ; e., 

 eggs in the gonads ; g. d., genital duct ; int., intestine ; int. c, intesti- 

 nal ca;ca ; /. n., lateral nerve ; /. v., lateral vessel ; sp., spermato- 

 zoa in the gonads. Magnified about 90 diameters. 



Fig. 5. Cross-section through head of the same individual, passing 

 through the front end of brain. 3^., third left eye-spot; ces., 

 oesophagus ; pb., proboscis in rhynchocoel. Magnified about go 

 diameters. 



