LINEUS. 277 



Fig. 6. Longitudinal horizontal section through intes- 

 tinal region, shewing the intestinal diverticula 

 alternating with the gonads. x 45. 



Fig. 7. Flask-shaped egg capsule, containing a single 

 embryo in the morula stage. (After M'Intosh.) 

 x .25. 



Fig. 8. Transverse section through intestinal region 

 passing between two diverticula. x 45. 



Plate IV. 



Fig. 1. Schematic figure, shewing the relations of the 

 various systems in the anterior end of the 

 animal as viewed from above. The proboscis 

 and its sheath, the oesophageal nerves and the 

 buccal vessels have been omitted. 



Fig. 2. Transverse section through lateral blood vessel. 

 On the side of the alimentary canal the paren- 

 chyma cells are smaller and complete. On the 

 outer side no cell wall is to be distinguished 

 away from the vessel. x 168. 



Fig. 3. Portion of oesophageal epithelium from a trans- 

 verse section. Three kinds of gland cells are 

 seen among the ciliated epithelium and below 

 it: — (a), (S), and (ft), (for explanation vide 

 text). x 168. 



Fig. 4. Two spermatozoa (after M'Intosh). x 700. 



Fig. 5. Larva of Desor as seen from the ventral surface. 

 The outer ciliated coat is not yet shed. (After 

 Barrois). 



Fig. 6. Young Lineus just hatched. x 40. (After 

 M'Intosh). 



Figs. 7-11. Diagrammatic sections through larvae of 

 Lineus at different stages. (After Hubrechl). 



