NOTES ON TELEOSTEAN OVA AND LARVAE. 17 



Ccdlionym.us lyra. Dragonet. 



Although most abundant in tlie months of March and April and of 

 rare occurrence during the summer, the presence of these eggs in the 

 plankton has been recorded from 11th February to 30th August, 

 the first and last occasion of the year on which searches for fish-ova 

 were definitely made. The diameter of the egg varied from 070 to 

 0-91 mm., the average for February to April being 0*796, May to June 

 0.803, July and August, 0'74. Post-larval stages from about 35 to 

 10 mm. were exceedingly common from April to August in the young- 

 fish trawl material. 



Pleukonectes. 



The paucity of the eggs of this genus in our samples is greatly due 

 to the fact that, by the time the systematic collection of samples was 

 commenced, the spawning season of the species occurring off Plymouth 

 was more or less over. Moreover, the regions favoured as spawning 

 localities by the plaice (P. ijlcitessa), dab (P. limanda), " merry-sole " 

 (F. microcephalus) are in the deep water at some distance from land, 

 to which there is a regular off-shore migration for the colder months 

 of the year, in which period most of the spawning of these species 

 occurs. The flounder (P. flesm) is an exception. Seven eggs of this 

 species were taken in four " hauls " in the Sound between 17th February 

 and 4th March, and post-larvae were common in May. No plaice 

 eggs were taken, the spawning being practically over by the end of 

 January. Previously published observations of the occurrence of plaice 

 eggs are confined to the records of the obtaining of one egg on 

 12th February and 7th March, 1902, by F. Balfour Browne (2, pp. 607 

 and 609). I myself have obtained no specimen of the pelagic post-larva, 

 nor is there any record of such having been taken at Plymouth, due, I 

 believe, to their off-shore spawning region. However, I hope to have 

 more to say as to the distribution of the young Pleuronectidae in a 

 later paper. 



P. microceplialus eggs have been most frequently met with, but on 

 five out of six occasions wlien this egg has appeared in my plankton 

 samples, it has been only a single specimen. The first specimen was 

 taken on 8th April and the last on 24th May, but before that period 

 no off-shore tow-nettings had been collected. The diameter of the egg 

 varied from 130 to 1'38 mm. A newly hatched larva measured 

 4'84 mm. Only one post-larva was taken — in July, off the Eddystone. 

 In previous years, however, this stage has been more abundantly 

 represented in our samples. 



No eggs of P. limanda were taken, and on two occasions only (in 



NEW SERIES. — VOL. IX. NU. 1. OCTUIiEI!, 1910. B 



