COE. — Nemerteans. 



PLATE 9. 



Figs. 59 to 61, Carinomella lactea Coe. 

 Fig. 62, Tetrasternma albidiun Coe. 



Fig. 59. Transverse section of body through the anterior sexual glands, and 

 near posterior end of proboscis sheath. The band of longitu- 

 dinal muscles (Imp) is beginning to diminish in size, the inner 

 circular muscles can hardly be demonstrated, and the proboscis 

 sheath is almost without muscular walls. The lateral nerves have 

 partially regained their original position between outer circular 

 miiscles and basement layer. The dorsal fibrous crossing is indi- 

 cated, but the ventral has disappeared. The ova are well devel- 

 oped, but their ducts are not yet formed. X 72. 



Fig. 60. A portion of a section from the same region as that shown in Fig. 

 58, PI. 9, more highly magnified. The relations of nerve core to its 

 cellular sheath, situated between it and the basement layer, are 

 shown. A very few delicate fibers of the outer circular muscle 

 apparently pass internally to the nerve core. A few connective 

 tissue fibers unite the sheath of the nerve core with the paren- 

 chyma about the lateral blood vessel. In this region all the nuclei 

 of the stomach epithelium lie deep in the cells. X 170. 



Fig. 61. Sagittal .section in about the same region as in Fig. 58, showing the 

 conspicuous transvei\se folds (a) of the epithelium of ventral side 

 of stomach. These folds are largely due to the contracted condi- 

 tion of the specimen. The thick band of longitudinal muscles 

 (Imp) is shown between rhynchocoel (re) and stomach. X 72. 



Fig. 62. Tetrastermna albldum Coe. Transverse section of body in intestinal 

 region, showing a peculiar condition in which the proboscis 

 sheath bends forward after reaching nearly to the posterior end of 

 the body. X 125. 



