of the Fishery Board for i^coUand. 271 



order. It is, however, difficult to discover characters which would enable 

 one to determine from an examination of one ray alone its position in the 

 series, and even more so to assign it to its proper species. 



When the branchiostegals are seen, in position on the fish, from the side, 

 they are all more or less bow-shaped, with the convexity on the anterior 

 side. 



The first three rays are much more slender than the remaining four ; 

 they have small smooth articular heads, and taper slightly. The 4th and 

 r)th rays resemble one another somewhat ; they are broadest at the head, 

 and from a little behind the head taper off gradually. The 6th and 7th 

 have usually falcate heads. The 7th is the broadest as well as the longest 

 ray. The 4th-7th branchiostegals show on the inner surface of the head 

 a flattened staooth articular surface. 



The rays, while being most noticeably bent in a vertical plane, as for 

 example in a side view of the fish, are very distinctly bent in another 

 plane ; and for the purpose of description the branchiostegals of the left 

 side of a lythe have been selected. 



If the ray is grasped in its upper half between the finger and thumb 

 of the left hand with its posterior edge facing the observer, a considerable 

 amount of curvature to the right or left will be noticed. This varies in 

 amount and direction in different rays. 



If the first ray be examined in the manner indicated, the bone is seen to 

 be bent to the right in its upper half and to the left in its lower, in shape 



resembling the letter S, thus \ . 



) 



The second ray is of similar shape to the first, but it is not so much 

 bent in either direction. 



The third shows a very slight bend to the right at the head, and a wide 

 sweep to the left in its distal half. 



The fourth is bent in only one direction, viz. to the left, in this 

 form ) . 



The fifth is bent in the same direction, but to a less extent than the 

 fourth. 



The sixth is almost straight, but shows a slight bend to the left at its 

 head. 



The seventh is bent to the left in the upper half and to the right in its 



lower, in shape suggesting a Z, somewhat in this form / . 



A certain amount of variation exists, but the above description will be 

 found, on the whole, fairly constant. The bend to the right (of the 

 observer) of the upper end is characteristic of the first two, and some- 

 times the third ray. The bend of the head to the left is characteristic of 

 the 4th-7th rays. These remarks apply to the saithe also. 



In the case of the cod the rays are not nearly so much bent to either 

 side as in the preceding. Thus the first is practically straight ; the 

 distal part of the bone is twisted to the left. The second is similar to the 

 first. The third is straight. The fourth shows a distinct curve on the 

 left side, that is the upper and lower ends are bent to the left. The fifth 

 is straight, and the 6th is slightly Z-shape. The seventh is very markedly 

 Z-shaped. 



The first three rays of the lythe are hyaline semi-transparent bones : 

 the first and second of the saithe are also hyaline, while the third is 

 partly so ; in the cod the first is hyaline, and the second partly of that 

 nature. 



In the branchiostegals of the saithe the transverse growth layers are 

 very distinct ; in the lythe they are also to be made out, although they are 



