14 Fifherij Board for Scotlond. 



The number of vertebree in three cases was 24. The lirst haemal 

 spine was on the eleventh vertebra. 



The otolith is convex on one side and concave on the other. Views 

 of both sides and also an edge view of the otolith ai'e given in 

 Figs. 52, 53, and 54. 



Comparison hetireen Ceidrodontas and Cnntharns. 



The two species may be confounded. The}' resemble one another 

 in the general shape of the body. If the upper jaws of Cantharvs be 

 retracted and the mouth shut, a specimen of this species might be 

 taken for a pale-coloured example of 8parus centrodontus. Some- 

 times the smaller Centrodontus (e.g., 20 cm. long) show little red 

 colour, and they may be mistaken for Cantharus, i.e., when the colour 

 is taken as a guide. 



The longitudinal rows are rather more marked in Cantharvs. The 

 eyes of that species are smaller than those of Centrodontus. 



Cantharus has a smaller mouth, and more and larger teeth, than 

 Centrodontus. They both have a prominent dorsal ridge in front of 

 the dorsal fin : that of Cantharus is the more acute. They differ in 

 the shape of the head, seen in profile. Centrodontus has a more 

 rounded and fuller snout, but the difference is not ahvaj^s easily 

 gauged. 



Cantharus has less body thickness, from side to side, than Centro- 

 dontus. 



The two species differ in the colour of the inside of the mouth, gill- 

 cover, and peritoneum ; vide pp. li and 13. 



The Reproductive Organ of 8parus cantharus. 



The reproductive organ resembles ihaXj oi centrodo-ntiis : it is herma- 

 phrodite. In a fish 40"5 cm. long, a predominant female, the ovarj" was 

 orange-coloured. A little testis was present along the lower border 

 of the ovary. The ovarian folds filled up the ovary (Fig. 48). These 

 folds are composed of digitiform processes filled with eggs. The 

 organ does not appear to have been ripe before. The yolked eggs 

 measured '35 mm. in diameter. Most of the eggs were small and 

 clear. Inhere was a slight pink sheen in the yolked eggs when they 

 were examined with the microscope. The &gg filled the follicle 

 almost completely. There were little masses of opaque yellow 

 pigment throughout the ovary. 



A fish 42 cm. long was a predominant male. The testis was small 

 and mottled. It had, I think, been spent. The ovary was a wdde 

 sac. Some small eggs were seen in the wall of the ovary. The 

 lacunar tissue in the wall of the ovary was very open. The external 

 aperture of the oviduct was closed. The virethra and vas deferens 

 opened hj the same external pore. In a second predominant male, 

 39 cm. long, the ovary was a wide sac, and a quantity of yellow 

 glandular-like bodies projected from the internal surface. In the 

 anterior region they were located all round the ovary, but in the 

 remainder of the organ thej^ were restricted in distribution ; in 

 the posterior part they were merely dorsal in position. They were 

 arranged in a manner g-enerally resembling the distribution of the 



