374 Part III. — TwentidJt Annual Report 



their average size was 111 '4 mm., or 4| inches. The males 

 exceeded the females in number, there being 557 ranging from 

 81 to 123 mm., and having an average length of 102.5 mm., or 4^^^ 

 inches. 



These averages show an increased growth in the 44 days from 

 September 4th of 4*9 mm. for the first series, or the youngest fishes, of 

 56 mm. for the females of the next series, and of '5 mm. for the males; 

 the increase for the males and females of the second generation com- 

 bined is 2"8 mm. Tliese increments agree pretty well with those in 

 other cases at the season. It is therefore not probable that the somewhat 

 different position of the ground where they were taken affected the 

 result. 



The next largest group in the Octobei- hauls was fairly well demarcated. 

 The females numbered 198, and ranged from 137 to about 175 mm., Avith 

 an average size of 155 '6 mm., or 61 inches. The males, 125 in number, 

 ranged from 124 mm. to apparently 158 mm., and had an average size 

 of 137'6 mm., or 6^-^ inches. It is possible, however, as an examination 

 of the curve indicates, that the males of this grovip end at 146 mm., and 

 that the next group commences at 149 mm. In that case the range 

 would be only 22 mm., and the average size 130'9 mm., or 5^ inches. 

 Comparison of the corresponding September averages indicates an 

 apparent increase in the interval of 1 '6 mm. for the females, and 0'7 mm. 

 for the males, taking the former average as correct. 



The remaining larger females, 23 in number, form a fourth group, 

 with a range from 176 to 203 mm., arid an average size of 184*5 mm., 

 or 7^ inches, an apparent increase of 1"6 mm. from 4tli September. 

 The males above 158 mm. number 3, viz. 166, 168, and 183 mm. If 

 combined they have an average size of 172-0 mm., or 6^ inches, which 

 would indicate an increase of 15-9 mm. from the corresponding Septem- 

 ber series (of 18 fishes). Probably, therefore, the one at 183 mm. 

 represents a succeeding group. 



A haul on 19th May 1901, in 65 fathoms, about 58 miles E. by S. 

 of Sumburgh Head, and thus about 25 or 30 miles north of the place 

 where the August and September hauls were made, yielded fewer 

 specimens, viz. 175, and of these 141 belonged to the first series. 

 Judging from the experience in some other cases, the small number of 

 the larger series in this haul may have been due to the temporary con- 

 gregation of the sexually matvire fish on some other spot in connection 

 with spawning. The 141 individuals of the first series ranged in size 

 from 52 to 92 mm., the average .size being 68'4 mm., or 2|-i inches. The 

 mean size was thus 15-1 mm. larger than in Octobei', the increment 

 representing the growth in the interval of 214 days during winter and 

 early spring. These fish were about fourteen months old (PI. XVII.). 



The next series, or those a little over two years old, was represented 

 by only fifteen females and nine males. The former ranged from 98 to 

 146 mm., and had an average size of 127'9 mm., or 5 inches, showing, 

 therefore, an apparent growth in the interval named of 16*5 mm. The 

 number of specimens is small, but the amount probably approximates to 

 the true growth. The nine males ranged from 113 to 138 mm., and had 

 an average size of 124'8 inm., or 4i|^ inches, showing an apparent growth 

 in the 214 days of 22*3 mm., which is evidently above the true growth, 

 owing to the absence of the smaller males, and the inconsiderable 

 number. A third group of fish a little over three years of age was 

 represented by six females and four males. The former ranged from 

 152 to 198 mm., with an average size of 170*2 mm., or 6J-g- inches, in- 

 dicating an apparent growth from October of 14"6 mm. The males 

 ranged from 151 to 179 mm., with an average of 167'0 mm., and 



