634 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Figure 20. — Anterior view of the leading edge 

 of pelvic fin of 240-min. specimen, showing 

 first four rays with process lying against 

 first ray (base of process imbedded in flesh 

 to the left of, or dorso-lateral to, the base of 

 the first ray). 



ossification is so far advanced it is considered of 

 similar size for this comparison. All 9 hypurals, 

 the uroneurals, the 3 epurals, and neural and 

 haemal processes have ossified; and some of the 

 centra are partially ossified. The lowermost prin- 

 cipal ray is attached to the anteriormost hypural, 

 as is the next ventral ray, a secondary. A 34.2-mm. 

 late metamorphic larva (fig. 14) showed partial 



ossification in all 85 vertebrae, development pro- 

 gressing anteriorly. 



The degree of ossification will separate lepto- 

 cephali from early metamorphic larvae for sizes 

 smaller than about 35 mm. Individual variation 

 in development in larvae exceeding 35 mm. rules 

 out this character for separating the larger larvae. 



REGRESSIONS OF BODY PARTS ON STANDARD 

 LENGTH 



Several measurements were selected to show 

 changes in form of various body parts and shift- 

 ing of the dorsal and anal fins anteriorly. 



The unique development of E. saurus precludes 

 depicting the regression of a part on the standard 

 length with a continuous line through all periods 

 of development. The size at which the lepto- 

 cephalus period ends varies with the individual 

 specimen, as does the size at which shrinking 

 ceases. I have no observations on living speci- 

 mens passing from the leptocephalus period to the 

 early metamorphic period, and few observations 

 on living specimens in the mid-metamorphic pe- 

 riod. I was unable to determine the average size 

 at which shrinking begins and the size at which, it 

 ceases. 



Figure 21. — Caudal osteology of 258-mm. E. saurus, 

 (modified from Hollister, 1936, p. 261, fig. 14). The 

 9 hypurals are indicated by the letter H, the 4 uro- 

 neurals are stippled, and the 3 epurals are crosslined. 



Figure 22. — Caudal osteology of a 31.3-mm. leptocephalus 

 (fig. 6). Density of stippling indicates intensity of 

 alizarine red stain. 



