of thr Fishery Board for Scotland. 



369 



Fig. 18. Pleuronectes platessa ; pectoral arch of right or eyed side from its inner 

 aspect, showing the ventral fins (V.) lying posterior to the base of the 

 clavicles (cl. ). 



Fig. 19. Rhombus maximus ; pectoral arch of left or eyed side from its inner aspect, 

 showing the cartilaginous anterior extension (c.V.) of the laminar por- 

 tion (l.p.) of the pubic bone (p.), the urohyal (u.) to which it extends, 

 and the consequently prolonged anterior position of the ventral fins 

 (V.) relative to the base of the clavicles (cl.). 



Fig. 20. Scophthalmus norvegicus ; pectoral arch of right or blind side from its 

 inner aspect, showing a further specialisation of condition found in 

 11. maximus ; the pubic bone (p..) has its origin from the base of the 

 clavicle (cl. ), and the ventral fins (V.) are directly under the anterior 

 extension of the urohyal (u. ). 



Fig. 21. Citharus linguatula ; pectoral arch of the right or blind side from its 

 outer aspect, showing the adnate position of the pubic bone (p. ) and 

 ventral fin (V.l. ) of the left or eyed side to the clavicles (cl.) ; both 

 pubic bones and ventral fins are posterior to the clavicles, and those of 

 the right or blind side (V.r. ) are siightly posterior to those of the left 

 (V.L). 



Fig. 22. Ibid. ; pubic bones, viewed slightly from ventral aspect, showing their 

 relative positions and their fusion posteriorly in a spine. 



Fig. 23. Arnoglossus later na ; pectoral arch of the left or eyed side from its inner 

 aspect, showing the transition from Citharus to Bothus; the left ventral 

 (V.l.) is prolonged in advance of the base of the clavicle (cl.), whilst the 

 right ventral (V.r.) stops short at the base ; the rays of the former are 

 widely separated from one another as in the turbot, those of the latter 

 are close together as in Citharus. 



Fig. 24. Solea vulgaris ; pectoral arch of right side from its inner aspect, showing 

 the short clavicle (cl.) and the posterior position relative to it of the 

 pubic bone (p.) and ventral fin, which is attached by a ligament only to 

 the urohyal (u.). 



REFERENCE LETTERS. 



A. — anal fin. 



a. | , a. 2 — articulating facets on post- 

 temporal. 



c. — continuation of first interhamial 



spine, 

 cl. — clavicle, 

 co. — coracoid. 



c.V. — cartilaginous continuation of l.p. 

 D. — dorsal fin. 



e. — ethmoid, 

 ep. — epiural. 



f. — frontal. 



hy., hy. 1 , hy. 2 — hypural elements. 



h. p. — hsemapophy ses. 



i. s. — first interhaemal spine, 

 l.n.o. — left nasal organ, 

 l.n.s. — left nasal sac. 

 1. — ligament. 



l.p. — laminar portion of pubic bone, 

 m. — maxilla, 

 n. — nasal bone, 

 n.s. — nasal sac. 

 o.o. — olfactory organ. 



pa. — palatine. 



p. — pubic bone. 



p. c. — post-clavicle. 



pm. — premaxilla. 



p. 1.— left pubic bone. 



p. p. — parapophyses. 



p.r. — primary ribs. 



p. t. — post-temporal. 



r.n.o. — right nasal organ. 



r.n.s. — right nasal sac. 



sc. — scapula. 



s. c. — supra-clavicle. 



s.p. — spinous process on pubic. 



s. terminal pubic spine. 



s.r. — secondary ribs. 



t. — turbinal. 



t.p. — transverse process 



u. — urohyal. 



ur. — urostyle. 



V. — ventral fin. 



V.l. — left ventra 



V.r. — right ventral. 



