L.M.B.C, MEMOIRS. 



No. VIII. PLEURONECTES. 

 (The Plaice.) 



BY 



F. J. Cole, Jesus College, Oxford, 



Lecturer in the Victoria University, Demonstrator of Zoology, 

 University College, Liverpool ; 



AND 



J. Johnstone, B.Sc, Lond., 



Fisheries Assistant, University College, Liverpool. 



Contents. 



Introduction. 



PAGE 



A. External Characters ... 4 



Asymmetry of Plaice 8 and 184 



B. Skeleton 11 



Skull and visceral arches... 11 



Vertebral column 40 



Median fins 49 



Limb girdles and paired 



fins 58 



C. Body Cavity and Viscera 63 



1. Coelomic Spaces G3 



2. Alimentary canal and 



glands 63 



3. Ductless glands 73 



4. Renal organs 77 



D. Blood Vascular System... 84 



Structure of Gills 87 



Pseudobranch 96 



E. 



PAGE 



Nervous System 103 



1. Brain and Si^inal Cord... 103 



'2. Cranial Nerves 110 



Component Theory Ill 



V.-VII. Complex 121 



N. Profundus V 125 



. X. Complex 138 



3. Spinal Nerves 145 



4. Sympathetic 156 



F. Sense Organs 163 



1. Lateral Sense Organs ... 163 



2. Nose 171 



3. Eyes 174 



Discussion of Asymmetry 8 



and 184 



4. Ear 190 



G. Reproductive Organs 193 



Appendix — Economic. 



A. Life History and Habits. — 

 Distribution and 



Spawning 199 



E 



B. Plaice Fisheries. — 

 Regulations and Remedial 

 ]\Ieasures 219 



