14 



EINAR LEA. 



[REP. OF THE "MICHAEL SARS" NORTH 



Fig. 8. Head of larva no. 10. l0 /i. 



of 10 mm. There are in all 144 segments: 81 preanal 

 and 63 postanal. All the fins contain rays, H , of the 

 caudal fin having seven and H 2 eight. Teeth are wanting 

 and the snout is rounded, protruding beyond the point 

 of the lower jaw. The nostrils are as described by 

 Schmidt. (See fig. 8). 



In our material we find four stages in the development 

 of this species. The first two stages, which may be called 

 preleptocephalic, are represented by nos. 1 to 6. The 

 next stage which may be called the typical leptocephalic 

 stage, is represented by nos. 7 and 8, while the fourth 

 stage, showing the beginning of the metamorphosis, is 

 represented by nos. 9 and 10. 



Besides these true larvae, there is a young individual 

 of Synaphobranchus pinnatus (no. 11), 114 mm in length, 

 still retaining some larval characters. It is quite compressed 

 and high in comparison to its length, having pigment 

 only in a stripe along the lateral line; its eyes are no 

 longer telescopic and its head ich much more elongate 



than that of the true larva (see fig. 9); the rays 

 of the anterior dorsal fins are 45 mm from the 

 point of the snout. In the collections from the 

 cruise there are also older individuals of the spe- 

 cies, in different sizes. They will be described 

 in another paper. 



The following table shows the station and 

 depth, as well as the length and degree of 

 development, for each of the larvae mentioned:— 

 It appears from this table: 1) that there are 

 two groups of larvae (represented by nos. 1 to 

 6 and nos. 7 to 10 respectively),the "prelepto- 

 cephalic" group not being more than 59 mm 

 long, the second group not less than 99 mm long; 

 2) that individuals belonging to both groups were 

 caught at one station; 3) that five individuals of 

 the "preleptocephalic" group were taken in depths of 

 50 to 150 m, while three individuals of the second 

 group were taken in 500 to 750 m ; 4) that the larvae are 



No. 



Station 



Depth 

 m 



Length of 



the larva 



mm 



Degree of 

 development 



1 



58 



150 



43 



Prelarva 



2 



62 



50 



47 



„ 



3 



34 



200 to 500 



50 



M 



4 



62 



50 



51 



„ 



5 



88 



50 



58 



»» 



6 



88 



50 



59 



» 



7 



92 



50 



99 



Full grown larva 



8 



87 



500 



107 



„ 



9 



98 



750 



107 



Larva showing traces 

 of metamorphosis 



10 



34 



500 



112 





11 



98 



750 



114 



Metamorphosis nearly 

 complete 



Fig. 9. Head of "semilarva" (no. 11). 



