12 6 Memoir Sears Foundation for Marine Research 



triangular; these characters at once distinguish the leptocephalus of this species from 

 that o{ Alhula vulpes. The myomeres are mostly quite distinct, 78 having been counted 

 in one of the specimens. A row of faint dark spots, which are much more distinct in 

 older leptocephali, is present on each side just above the alimentary canal. 



Three leptocephali, 42, 42, and 44 mm long, are the longest larvae in the collec- 

 tions studied and may represent about the maximum length attained in the leptoceph- 

 alus stage. Here development has progressed somewhat beyond that of the specimens 

 described above, for the rays are evident now in the dorsal and anal fins, though an 



Figure 21. Elops sauna, above, leptocephalus, 35 mm long; below, young fish, 20 mm TL, recently trans- 

 formed. 



accurate enumeration cannot be made. The anal fin is removed from the base of the 

 caudal by a distance shorter than the head, and the primitive membrane has remained 

 between the two fins. The pectoral fins are represented by tufts of membrane and 

 the pelvics merely by thickened places in the abdominal wall where their bases are 

 developing. Seventy-seven myomeres were counted in one of the specimens. 



In a considerably older specimen, reduced in length to 27 mm, the body, though 

 still quite flat, has become much more substantial than in the younger stages described. 

 The dorsal and anal fins are sufficiently developed to permit an accurate enumeration 

 of the rays, and the anal fin is now well separated from the caudal. The primitive mem- 

 brane has disappeared behind the fin, though a short section of it remains in front. 

 The pectorals are rather well developed and show signs of rays. However, the pelvics 

 are undifferentiated. 



A virtually young adult only about 16 mm long (not in good condition) represents 

 the maximum "shrinkage" in length during metamorphosis, among specimens studied. 

 Though the body has become rather robust, the head and especially the snout remain 

 depressed. The fins, except for the pelvics, are rather well developed. The intestinal 

 canal remains loosely attached to the abdomen as in younger fish, and the primitive 

 rows of dark dots on each side of the canal are distinct. 



The state of development varies widely among the rather numerous young adults, 

 18 mm and upward. For example, a specimen scarcely 20 mm long is fully as well 



