PATELLA. 



2(58 



/,'./?. P. = Renal aperture of reno- 



pericardial canal of right 



kidney. 

 B.S. — Radular sac. 

 S.C. = Sense cell of eye. 

 Sec.F.Cr. = Radial secondary 



folds on the transverse crop 



folds. 

 Sec.G. = Secondary or pallial gills. 

 S.L.P. = Sub-lingual pouch. 

 S.M. = Shell muscle. 

 S.-B.. Lobe. = Sub-rectal lobe of 



right kidney. 

 S.B.M. = Sub-radular membrane. 

 St. = Stomach. 



S( . Gr. — Groove in stomach- wall. 

 Sub-Ep.N.L. = Sub-epithelial 



nervous layer. 

 Sub-Ocs.C. = Sub-oesophageal 



connective of visceral loop. 

 Sup.-Int. = Supra - intestinal 



ganglion of visceral loop. 

 S.Z. = Sensory zone of mantle 



epithelium. 

 T. = Tentacle. 

 T.N. — Tentacular nerve. 



V. Visceral loop. 



Vac.E. — Vacuolated epithelium 

 beneath lateral streak. 



V.F.G. = Ventral fold of gullet. 



V.G. — Visceral ganglion. 



V.H. = Visceral hump. 



V.L.C. = Ventro-lateral cartilage 

 of the odontophore. 



V.-l.F. = Ventro-lateral folds of 

 wall of rectum. 



VI. = Veinlet from mantle edge. 

 V.-Lobe. = Ventral lobe of right 



kidney. 

 Vn. = Ventricle. 

 V.St. = Valve hindering flow of 



secretion of hepato-pancreas 



into anterior part of gut. 

 X is the point of connection 



between Int. 1 (Fig. 10a) and 



Int. 2 (Fig. 106). 

 Y. is the point at which the 



stomach folds on itself 



(Fig. 10ft). 

 Z. is the anastomosis between 



the posterior pallial nerves 



of the two sides. 



The terms right and left are always used to signify post-torsional 

 relations unless otherwise specified. 



Fm. 1 



Fii 



Fig. 

 Fig. 



Plate I. 



Extreme foniis of shell of Patella vulgata. From 

 specimens collected in the Gouliot Caves, Sark. 



Section through the shell. A Thin brown external 

 layer. B Thick middle layer : (a) outer part 

 traversed by branching canals ; (b) clear inner 

 part. C Internal laminated layer, x 15. 



The animal in its shell — Ventral surface. H. = Head. 



Dorsal view to show positions of organs. The 

 pigment layer of the mantle has been rubbed. oft' 



