138 Memoir Sears Foundatio?i for Marine Research 



fins. The intestinal tract has become more fully invaginated and no longer remains 

 merely attached, except posteriorly, as in younger fish; the vent, instead of being sit- 

 uated at the origin of the anal, is now well in advance of it, having moved forward 

 rather more rapidly than the fin. The color markings remain about as in the younger 

 fish described, but additional chromatophores have appeared, principally at the occiput, 

 at the base of the dorsal, and on the dorsal. 



The smallest specimen that may be classed as a young adult is 28 mm (2 i mm SL), 

 and its length is the least of the many Alhula at hand. This fish is quite a little longer 

 than the one that diminished from a leptocephalus to a young adult of only 20 mm, 

 in an aquarium (jp: 269; 40: 109). The body remains more compressed in this 

 and other young adults than in large adults, and it is also more slender, the depth at 

 the dorsal origin 6.5 times in SL. The head is contained 3.45 times in SL and there- 

 fore does not differ in this proportion from large adults. The eye is rather small, 5.05 

 times in head, and is definitely shorter than the snout, which is contained 3.05 times 

 in the head and projects rather prominently beyond the mandible; the maxillary ex- 

 tends to the anterior margin of the pupil and is contained 2.9 times in head. The dorsal 

 and anal fins have continued to move forward, the origin of the dorsal now being equi- 

 distant between base of caudal and tip of snout; and the attachment of the pelvic fins is 

 now only a little in advance of the middle of the dorsal base. At this stage, and even in 

 ones a little older, the two dark lines along the sides of the intestinal tract in the lepto- 

 cephali persist, two rows of dark spots on the back (described elsewhere) have appeared, 

 there are indications of some elongate dark spots along the side, and some additional 

 pigment has appeared on the base of the anal and ventrally on the caudal peduncle. 



Scales first appear in young adults about 35 mm long. At a length of 40— 45 mm, 

 scalation generally is complete, except perhaps on the abdomen. At these stages the 

 lateral line also is well developed. The dorsal and anal fins are situated approximately 

 as in large adults; that is, the origin of the dorsal is somewhat nearer to the tip of the 

 snout than to the base of caudal, and the anal is separated from the caudal by a distance 

 somewhat greater than the length of the snout. The pelvic fins, which, from the time of 

 their appearance in the leptocephalus, are inserted a little nearer to the head than to 

 the base of caudal, retain that relative position and are now about under the middle 

 of the dorsal base. The pectorals are long but not falcate and reach more than halfway 

 to the pelvics. The vent has continued to move forward and is now in advance of the 

 anal by a distance nearly equal to the length of the snout. 



At 40 mm, pigmentation has become general and the nine crossbands on the 

 back, described elsewhere, are prominent. But dark longitudinal stripes do not appear 

 definitely until a length of about 75 mm is attained, at which size the crossbands have 

 become obscure. 



Spawning. The spawning season and the spawning grounds remain unknown. 

 Most of the many larvae and young adults described herein were taken off the coast 

 of Panama during February and March, but their occurrence at other seasons is not 

 known, as no year-round collecting has been done there. Growth stages ranging from 



