ON TURBELLARIA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 137 



EXPLANATION OF FIGURES. 



aij. Anterior gut root or its branches. mu. Muscular layer of body wall. 



br. Brain. mu.s. Sphincter muscle of pore canal in fig. 3. 



br.e. Eyes belonging to the brain area group, p. Dorsal pore. 



ep. Surface epithelium. pe. Penis. 



fa. Female aperture. ph. Pharynx. 



fo. Female organs (undeveloped) in fig. 3. p.ho. Internal opening of pharynx. 



(j. Main gut. ph.s. Pharyngoal sac. 



g.\. First lateral gut root. pa. Penis sheath. 



(j.2. Second ,, . Sucker. 



g.3. Third sij. Shell gland. 



t/r.g. Granule gland (prostatic vesicle). t. Tentacle. 



m. Mouth. vs. Vesicula seniiualis. 



ina. Male aperture. ut.d. Efferent canal of uterus. 



me. Mucous canals in the muscular tissue behind ut. Commencement of uterus, 

 pharyngeal sac. 



DESCRIPTION OF PLATE. (For lettering see above.) 



Fig. 1. Sagittal section of Aceros stylustomoides (specimen a). 



Fig. 2. Dorsal pore of A. sti/lostomoides (specimen b). The canal is oblique and of considerable length, 

 its lumen being fairly uniform but slightly contracted near its inner and outer ends. The cells lining it are 

 richly ciliated. 



Fig. 3. Sagittal section through genital legion of immature Nuchenceros orcailensit*, highly magnified. 

 Description on p. 135. There is no connection at this stage between the various cavities and the external 

 surface. 



Fig. 4. Sagittal section of NucJienceros orcadensin (specimen b). 



Fig. 5. Sagittal section of JV. orcadensis (specimen a). 



Fig. 6. Longitudinal section of N. orcadensis (specimen a), passing through the tentacle on one side. 

 The absence of visceral branches in the substance of the tentacle will be noted. 



(ROY. soc. EDIN. TKANS., VOL. XLV., 827.) 



