30 



EINAR LEA. 



[REP. OF THE "MICHAEL SARS" NORTH 



The features giving this species a very characteristic 

 appearance are: 1) the two swellings on the alimentary 

 canal, seen in fig. 3 pi. V, 2) the 9 or 10 large subcuticular 

 nearly equidistant pigment spots along the sideline of the 

 body, 3) the situation of the anus (on the foremost third 

 of the body), and 4) the position of the dorsal fin. Even 

 in individuals which must be regarded as not yet fully 

 developed, we find the foremost interspinous elements 

 very near the head. 



The muscle segments are very numerous, between 

 218 and 229, 55 to 58 of which are preanal in individuals 

 whose metamorphosis is not yet far advanced. 



As a rule, the caudal fin contains 6 rays, three in 

 Hi, and three in H2, which are considerably longer than 

 the hindmost rays of the vertical fins. The tip of the tail 

 is very pointed. 



The teeth are not very large. In each half of the 

 upper jaw we find anteriorly a small curved tooth, then 

 a rather long thin curved tooth followed by 14 to 18 

 sloping straight teeth, the anterior 8 larger than the rest. 

 In each half of the lower jaw there is first a curved tooth 

 followed by 10 to 16 sloping straight teeth decreasing in 

 size backwards. 



Besides the spots of pigment along the lateral line, 

 there are numerous small dots on the two swellings of 

 the alimentary canal, and on the head, or rather in the 

 head, we find pigment on the brain portion at the back, 

 and in the front on the portion between the two nostrils 

 (the pigment on the brain is indicated in figs. 28—31, 

 but it was found impossible to adequately reproduce the 

 pigment on the nostrils). As a rule there is pigment 

 along the lower edge of the upper jaw (see figs. 28 — 31). 



In the following table the individuals are arranged 

 according to their degree of development: 



near the upper margin of the head have I been able to 

 see a few mucous pores, which later increase in number 

 on the head. 



Snout in both specimens very much pointed. 



Fig. 28. Head of L. stylurus, no. 1 



No. 3 does not diverge greatly in regard to develop- 

 ment from nos. 1 and 2. 



It is a little larger, and has more true rays in the 

 vertical fins. Anterior nostril more tubular in shape. 

 Mucous pores observed only along the upper margin of 



Fig. 29. Head of L. stylurus, no. 4. 10 /i 



the head. Of the larvae showing no trace of retrograde 

 metamorphosis, this specimen is the most fully developed. 

 No. 4 represents the beginning of the metamorphosis, 

 as evidenced by its lesser height and its longer snout 

 with rounded point (see fig. 29 and table). The anterior 



G 



z 



3 

 



Q 



"5)3 



3 E 

 CI c 



Greatest 

 height 



Dorsal 



Anal 



Head 



Snout 



Eye 



Number of 

 muscle-segments 



Number 



of caudal 



rays 



Number of 

 teeth in 

 half jaw 



E 

 E 



u_ — 



-2. c 

 a> 



E 

 E 



o> 



E 

 E 



m- .3 

 ° M 

 -S 3 

 (U 



E 



E 



_ .3 

 -S 3 



<u 



E 

 E 



S--3 



E 

 E 



0^ 



S-.3 



cy "re 

 O- re 



"to re 

 O 3 





X 





a. 

 0. 







1 



2 

 3 

 4 

 -j 

 6 



39 



150 



■ 



» 



93 

 93 



105 



100 



127 



78 



7 

 6 



7 



6 



7-5 

 3 



7-5 

 65 

 6-7 

 6-0 

 5-9 

 3-8 



10 

 10 

 12 

 11-5 

 13 

 8 



10-8 

 10-8 

 11-4 

 11-5 

 10-2 

 10-3 



30 

 32 

 31 

 32 

 42 

 22? 



32-3 

 34-4 

 29-5 

 320 

 33-1 

 28-2? 



4-3 

 4-3 

 4-6 

 51 

 5-2 

 4-9 



4-6 

 4-6 

 4-4 

 51 

 4-1 

 6-3 



1-7 

 1-7 

 1-8 

 21 

 2-2 

 21 



39-5 

 39-5 

 39-2 

 41-2 

 42-3 

 42-8 



0-8 

 0-9 

 0-9 

 0-9 

 1-0 

 10 



18-6 



20-9 

 19-6 

 17-7 

 19-2 

 20-4 



58 

 58 

 57 

 55 

 37 

 ? 



171 

 168 

 167 

 163 

 188? 

 ? 



229 



226 

 224 

 218 

 225? 

 >218 



4 

 3 

 3 

 3 

 3 

 4 



3 

 3 

 3 

 3 

 3 

 3 



16 

 18 

 18 

 20 

 16 

 16 



11 



14 

 14 

 17 

 14 

 15 



Nos. 1 and 2 are not fully developed, for rays are nostril is very distinctly tubular, approaching nearer to 



wanting in the vertical fin except near the caudal fin. the point of the snout than it does in the previous 



At this developmental stage the anterior nostril hat not specimens, and more internal pigment is developed in 



yet grown so distinctly tubular as it does later, and only the hinder portion of the head. 



