218 Mr. 0. Holmqvist on Fishes collected during 



accounted for by the immaturity of the individual." Liitken, 

 in the ' Dijmphna-Togt,' makes nearly the same statement, 

 but with the modification that the lateral line ends in very 

 young individuals exactly above or in front of the anal fin ; 

 in other cases variation in the extension of the lateral line 

 may be due to difference in locality. 



An examination of the numerous specimens obtained during 

 the Peary Expedition plainly indicates that the extension of the 

 lateral line stands in an almost constant ratio to the age of the 

 fish without regard to locality. In the smallest individuals — 

 about 30 millim. in length — it is reduced to a few slight 

 tubercles just in front of the anus ; the lateral line is 

 extended more backward, with very little variation, in 

 proportion to the size of the fish, reaching to the caudal in 

 all tolerably grown individuals. Excepting in very young 

 individuals, the spines of the lateral line are nearly always 

 stronger than those of the dorsal line. The lateral line 

 begins with fully developed spines close to the upper 

 corner of the gill-opening. The tubercles of the dorsal line 

 appear some distance behind the commencement of the lateral 

 line as small points that increase in size backward, and 

 eventually become transformed into ordinary thorny spines. 



Only one specimen (a small female from Ingleheld Gulf) 

 has a slight and thin row of tubercles on each side at the 

 base of the anal ; the other specimens show no trace of such 

 an appendage. Neither has Liitken seen these spines in any 

 of the sixty-six specimens of the ' Dijmphna-Togt.' Their 

 occurrence may be considered exceptional, or, perhaps, re- 

 stricted to certain localities, especially, according to Collett *", 

 the Scandinavian coasts f. 



Most of the specimens in this collection possess a row of 

 tubercles behind the pectorals. In the specimens where this 

 row is most strongly developed it runs into the lateral line 

 close to the points of the pectorals. 



* L. c. p. 36. 



t The only Scandinavian specimen I had an opportunity of seeing 

 is very young, and was dredged (July 1895) by Dr. Carl Aurivillius 

 from a depth of 40-70 fathoms in Koster Bay (Northern Bohtislan). 

 Its total length is 17 millim. No spines in the lateral line or behind 

 the pectorals. The spines of the dorsal line are well developed and reach 

 to the caudal ; they originate on the skull, being throughout long and 

 sharp. The foremost pair of parietal tubercles slightly marked. The 

 upper praj opercular spine simple and bent upwards. No spines along the 

 base of the anal. 



