322 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



PLATE 31 



Fig. 41. Ototyphlonemertes spiralis. A, outline of anterior portion of 

 body showing statocysts {st) on ventral ganglia; other let- 

 ters indicate: cl, cephalic blood lacunae; dg, dorsal gang- 

 lion; In, lateral nerve cord; p, proboscis; ps, proboscis 

 sheath. B, statocyst with spherical statolith. C, stylet region 

 of proboscis, showing slender stylets and basis and tubular 

 middle chamber (rnc). D, stylet of larger and smaller 

 individuals, indicating spiral ridges. 



Fig. 42. Tetrastemma nigrifrons. Variations in color patterns, rep- 

 resenting 4 color varieties: pallidum (a and d), hicolor (b), 

 zonatum {c), and purpuratum (e). In some specimens the 

 dark cephalic marking is more or less completely united 

 with the pigmentation of the dorsal surface of body. 



