Gatty Marine Laboratory ^ St. Andrews. 249 



effect being heightened by the orange tint of the inner surface 

 of tlie anterior rays. At 20 inillim., when the lateral spines 

 are developing, the pre-, post-, and interocular bands are still 

 present, though the latter (often greenish) is less distinct. 

 Above 20 millim. the body (as at 25 millim.) becomes more 

 uniformly tinted, such as olive or bluish green, the ocular 

 belts being indistinct ; but at the size just mentioned (25 

 millim.) the sides of a green example are somewhat silvery, 

 the first dorsal has a brown tip, and the orange tint remains 

 in the pectorals, thus contrasting with the generally paler hue 

 of the ventral surface. 



It is interesting that in these small forms slight pressure 

 causes the sucker to adhere in the dead animals. It is, of 

 course, easily removed. 



When 11 millim. long in spirit, in June, it conforms rather 

 to the 20 millim. stage of Agassiz, since the first dorsal is 

 long, fleshy at the base, and with crenations to represent rays 

 at the tip. The breast-tins have increased in size, though 

 they do not differ much in their relations to the posterior 

 border of the dorsal, since that has been carried considerably 

 backward by the elongation of the fin-rays. The second 

 dorsal and the anal are prominent, and the caudal has no 

 trace of the larval tail. 



Little change ensues up to 17 millim., except the general 

 increase in bulk, the deepening of the first dorsal, and the 

 more evident crenations at the tip. When about 18 millim., 

 however (in spirit) , four rows of simple papillae appear : — 

 (1) A line of minute and somewhat closely arranged papillae 

 along the dorsal ridge and extending trom the posterior part 

 of the head to the base of the first dorsal ; behind the latter 

 two rows occur, and they cease before the commencement of 

 the second dorsal. (2) A line of small papillae extending 

 from the tubular nostril along each ocular ridge, and sloping 

 downward along the dorso-lateral region, but ceasing opposite 

 the first dorsal. (.B) A series of five larger, but still simple 

 papillag, from a point above the base of the breast-fin to a 

 vertical line from the vent. (4) A similar number along 

 each ventral edge to the commencement of the anal fin. The 

 third line has the best marked papillae. 



It is interesting that in the American examples Professor A. 

 Agassiz found no trace of these papillae in fishes 20 millim. 

 long ; yet the anterior part of the body, he observes, had 

 assumed the somewhat angular outline characteristic of the 

 adult, though the body as a whole was longer. Indeed, he 

 found the spiny tubercles (of which the foregoing papillae are 

 the precursors) developed only to a slight extent in young 



