352 



E. S. CLARK. 



interspinous regions. Over the whole surface of the body there is a 

 mixture of large and small stellate chromatophores, and smaller black 

 dots. The unpaired fins are still unpigmented. The anterior half of 

 the first dorsal fin has an aggregate of black chromatophores. The snout 

 region has the least amount of pigment. 



The spawning of the dory, according to Cumiingham,* takes place 

 during June and July. Heffordf obtained ripe ovarian eggs on 31st 

 AuDust, while HoltJ observed spent dories in June off the west coast of 



Fig. 2.— Zeus fuher. Length 6 mm. Oithona Station, CXI. A. 3rd Sept., 1913. Total 

 depth 32 fms. Midwater haul. 

 Del. E. Ford. 



Ireland. The post-larvse recorded in the above table suggest a spawning 



period extending from July to the beginning of September, though it 



is probable from previous records that spawning may also occur in June. 



Cunningham* worked out the rate of growth of the dory, and gave 



lengths of about 130 mm. at the end of the first year, and about 280 mm. at 



the end of two years. The usual length of the dory landed at the Plymouth 



Barbican is from 15 to 18 inches, which, as Cunningham remarks, " is 



probably not reached in less than three years." On examining the rings 



of growth on the opercular and hyomandibular bones (especially on the 



cerato-hyal), according to Heincke's method, § I find the results agree 



with those of Cunningham, though not many specimens were examined. 



The material was secured by the OitJiona in the Agassiz and otter trawls. 



Group. I Group. II Group. 



<150 mm. 



ca. 150-ca. 250 mm. 



ca. 250-ca. 350 mm. 



* Jour. M.B.A. N.S., 2. 1891-2. 

 X Rep. Roy. Dublin See. 1892. 



t Journ. M.B.A. N.S., 9. 1910. 

 § Intern. Meeres. Jahresbericht, 4-5. 



