74 J. H. ORTON. 
State of sexual organs is classified in 7 stages (Publications de Circon- 
stance, No. 53, p. 35). 
Stage I. Virgin individuals. Very small sexual organs close 
under vertebral column. Q wine-coloured torpedo-shaped 
ovaries about 2-3 em. long and 2-3 mm. thick. Eggs invisible 
to naked eye. g whitish or greyish-brown knife-shaped testes 
2-3 em. long and 2-3 mm. broad. 
Stage IT. Maturing virgins or recovering spents. Ovaries some- 
what longer than half the length of ventral cavity, about 1 cm. 
diam. Eggs small but visible to naked eye. Milt whitish, some- 
what bloodshot, same size as ovaries, but still thin and knife- 
shaped. 
Stage III. Sexual organs more swollen, occupying about half of 
ventral cavity. 
Stage [V. Ovaries and testes filling two-thirds of ventral cavity. 
Eggs not transparent. Milt whitish, swollen. 
Stage V. Sexual organs fillmg ventral cavity. Ovaries with 
some large transparent eggs. Milt white, not yet running. 
Stage VI. Roe and milt running (spawning). 
Stage VII. Spents. Ovaries slack with residual eggs. Testes 
baggy, bloodshot. 
Doubtful cases are indicated by quoting two stages, e.g. St. I-II, 
St. VII-II, ete. 
Then attach label to fish and count 
(17) Serial number of first vertebra having complete hzmal arch.* 
(18) Total number of vertebre. 
METHOD OF WORK. 
The measurements and weighings of the fish were first made and the 
counting of the scales and fin-rays accomplished in a second series of 
operations, and finally the skeletons were prepared in a third stage. 
It was found possible to take the weight and measurements of only 
250 fish in the first sample and 300 fish in the second sample within 
24 hours of the landing of the fish, but weights and measurements of 
the whole samples of 550 and 525 respectively were completed within 
less than 36 hours of the landing of the fish. The fish not examined 
on the first day were kept in an ice chamber until required and remained 
in good preservation. It may here be noted that both the larger samples 
were obtained from steam-drifters, on which boats it appears that the 
fish are subjected to rougher handling than on sailing drifters. Some fish 
* The figures given in Tables I, III, and IV denote the number of vertebra with 
perfect and imperfect hemal arches. For details see pp. 80-82. 
