384 



SfAXDIN'AVIAN FISIIKS. 



depth of the body, which occurs at its middle (exclud- 

 ing the caudal tin), being about "/j of the total length 

 to the end of the caudal fin". The greatest thickness 

 of tlie bod}' always lies behind the head (in the ab- 

 dominal region or the anterior jjart of the tail), and 

 is more than ',3 of the length of the head''. 



The head is small, its length being always some- 

 what less than that of the caudal fin, and varying in 

 full-grown specimens betAvcen 1 5 % (according to Gott- 

 SCHE 14 96) and 1672^ t'f ^l^^ total length of the body, 

 or between 18 and 20?^ of the length to the base of 

 the caudal fin. The mouth is small, the gape being 

 scarcely curved at all; and the jaws are of erjual pro- 

 jection and furnished \\ith round, thick lips. The length 

 of the lower jaw varies between 4 and 5 % of the length 

 of the body or about 40 and 53 % of the least depth 

 of the tail. The jaw-teeth are even, broad, and close- 

 set in a single row; they are present in botli jaws, but 

 oftenest, in the upper jaw at least, only on the blind 

 side. The eye side of the jaws is toothless or some- 

 times furnished with 1 — 3 teetli. Sometimes one or 

 two of the front teeth are longer than the rest. The 

 upper pharyngeal teeth are comparatively few, 3 or 4 

 on each of the three upper pharyngeals on each side, 

 and are imbedded in a thick, loose skin on the roof 

 of the pharynx. In shape they are flat, curved, trian- 

 gidar, and sharpl}- pointed, like miniature Squaloid teeth. 

 (_)n the lower pharyngeals they are more scattered and 

 narrower, more dagger-like'". The gill-rakers are middle- 

 sized, setiform, and fairly close-set: we have found their 

 number on the first branchial arch to be 22. The gill- 

 openings are uncommonly small, partlv because they 

 do not extend higher than the top of the base of the 

 pectoral fins — the entire upper margin of the opereula 

 is united by the skin to the body — partly because the 

 branchiostegal membranes are in great part coalescent 

 inferiorly, forming a fold up-\vards and inwards that 

 fits into the bend of the urohyoid bone, above the point 

 of the lower extremity of the clavicular bones. To this 

 folding of the branchiostegal membranes is due the 

 peculiarity that the last three of the seven branchio- 

 stegal rays lie close together under the martrin of the 



gill-opening; and as the first branchiostegal ray is small 

 and almost invisible, the casual observer finds oidv three 

 branchiostegal rays on each side. On the eye side of 

 the l)odv the margin of the ijill-cover has a somewhat 

 thick, orange rim, and a similar rim ap))ears on the 

 clavicular bone (behind the margin of the gill-opening), 

 in front of the liase of the pectoral fin. The eyes are 

 set on the right side, are large and \er\' pi'ominent, 

 and lie so close together that they are separated only 

 by a sharp osseous ridge. The longitudinal diameter of 

 the upi)er orbit is fully half the lengtli of the cranium 

 from the head of the vomer to tlie large occipital fora- 

 men; liut the eves themselves are so covered with der-- 

 mal folds that the visible part of the eye is compara- 

 tively small. During the growth of the fish from 20 

 to 30 cm. the length of the visible part of the upper 

 eye diminishes, according to Kiuiyer'.s measurements, 

 from 28' '3 to 19\/^ % of the length of the head or, ac- 

 cording to ovu' measurements, from 26''2 to 2IV3 % 

 thereof. The lower eye, which is somewhat smaller 

 than the upper, lies only a little further forward. The 

 nostrils resemljle those of the preceding species. They 

 lie fairly near each other, on the eye side nearly in a 

 line with the corner of the nioutli and almost between 

 the eyes. The nostrils of the blind side lie almost 

 exactly at the dorsal edge of the snout, in front and 

 to the right of the beginning of the dorsal fin, nearly 

 in a line with the anterior margin of the u])per eye. 



The scales cover both sides of the body, the head 

 (excepting the eye side of the snout), the ra}-s of the 

 vertical fins, the outer side of the base of the pectoral 

 fins and of half the ventral fins, and sometimes a part 

 of the inner side of the last pair of fins as well. The}' 

 are thin, smooth at the raai-gin, oval, and (on the body) 

 imbricated. On the head they are nearly round, smaller 

 than on the body, and not imbricated. The lateral line 

 is straight, with a slight, but distinct, arched curve above 

 the pectoral fins. This arch seems generally to be higher 

 on the blind side than on the eye side, but its height 

 and shape are subject to individual variations. 



The dorsal fin begins somewhat behind the anterior 

 margin of the upper eye, but distinctly on tlie blind 



" In this respect Uiis species is nuire variable Uian tlie preceding one. According to (.ur nieasurcnients of 6 specimens between 15 

 and 31 cm. loni;, from Boliusliin and Norway, (be greatest deptli of the body varies between 35 and 38 % of tbe length to the end of the 

 caudal tin, or 42' ., and 40 % of the length to the base of the caudal fin, the proporlions being highest in the largest specimens. According 

 to GOTTSCHE the former proportion varies between 36' ., and 45 "», and according to Kroyeh between 32 and 40 %. 



According to our measurements the greatest thickness of the body varies between 34 and 40 % of the length of the bead, accord- 

 ing to Kuoyer's measurements between 40 and 43 % thereof. 



' KltOYER has found them to be set in two rows. In our specimens they are set in a single row. 



