472 H. J. FLEURE AND MURIEL M. GETTINGS. 



Fig. 1. — The jaw-plates of Trochus crass us, Mont. 



Fig. 2. — A sectiou of the jaw-plates. 



Fig. 3. — Cells from the strengthening tissue beneath the jaw-plates. 



Fig. 4.— The roof of the branchial cavity in Trochus crassus, Mont. 



Fig. 5. — The roof of the branchial cavity in Trochus obliquatus, Gmelin. 



Fig. 6. — An oblique transverse section of a gill leaflet of Trochus. 



Fig. 7.— Section of the roof of the branchial cavity and gill of Trochus. 



Fig. 8. — Section of the roof of tlie branchial cavity and gills of Haliotis. 



Fig. 9. — Section of the left kidney of Trochus in the region of the nephri- 

 dial gland. 



Fig. 10.— Epithelium of left kidney of Trochus. 



Fig. 11. — Epithelium of right kidiiry of Trochus. 



Fig. 12. — Epithelium of nephridial gland of Trochus. 



Fig. 13. — Section of pericardium of Troclius showing the blood channels 

 which feed the left auricle. 



Fig. 14. — Epithelium of the right kidney of Haliotis. 



Fig. 15. — Epitlielium of the left kidney of Haliotis. 



