of the Fishery Board for Scotland. 



113 



estimation of the plankton was not an essential part of the investigation. 

 I have therefore not attempted to estimate exactly the quantities of plank- 

 ton, and have taken the rough volumetric measurement as a sufficient 

 standard of comparison in the present case. 



In Tables I.V.-XI. are given the volumes of Copepoda taken in 

 each net, on each station. With the volume of the take there is 

 given, by means of letters, some indication of the composition of the 

 collection. The letters used and their significations are as follows : — 

 a = large Copepoda, e.g. from about 2 , 2-3'5mm. in length (cf. CaJanus) ; 

 y = small Copepoda, e.g. from '8-1 "6mm. in length; E = pelagic 

 Crustacean eggs,* apparently belonging to a Copepod. This egg measures 

 •35mm. in diameter. There is a large perivitelline space, and the zona 

 has a diameter of , 65mm. It was obtained in all stages from that of 

 early segmentation to the formation of the nauplius. The letters l.q. 

 mean large quantity ; Z means Zoese, and M, Hydromedusse ; C stands for 

 Copepoda. 



When the letters are used without numbers each signifies, if used alone, 

 that the take consists wholly of the one form which the letter stands for; 

 when accompanied by other letters the presence of individuals of that form 

 is noted. In order to show the proportions in which the Copepoda, Zoese, 

 Medusae, etc., are present, figures are joined with the letters, and signify 

 that so many parts of the collection consist of one or the other group. 

 Thus 2 y., 1 a., 3 Z., 5 E., M, serve to record that the tow-net collection 

 consists of 2 parts of small Copepods, 1 part large Copepods, 3 parts 

 Zoese, 5 parts pelagic Crustacean eggs ; M indicates the presence of 

 Hydromedusai. 



The following particulars refer to the relation between the volume and 

 the number of Copepods in different months and on different stations. 

 They may serve as a basis for comparison with other localities. 



January. Station L, Vertical Net, Volume 6 - 5cc. = 1531 Copepods. 

 February. „ III., ,, l-5cc.=360 ,, 19 Zoese. 



,, IV., ,, 5-5cc.=1828 



March. ,, L, ,, ,, 2cc.=276 ,, 9 Zoese ; 



59 Crustacean eggs. 



,, II., ,, ,, lcc.=95 Copepods; 50 Zoese; 



180 Crustacean eggs. 



,, ,, ,, 6-fm. Net, ,, '5cc. =334 Copepods (y.) ; 198 



Zoese ; 521 Crustacean eggs and Nauplii. 

 April. ,, L, I-fm. Net, Volume 6'5cc. (4 y., 1 a.)=3,500 Copepeds. 



May. ,, I., Vertical Net, 1,000 Copepods (2 y., 1 a.)=2'5cc. 



5, 



„ II., 



1,000 



(ly.,2a.)=3cc. 



33 



» HI., 



1,000 



,, (a.)=5cc. 



3 3 



„ iv., 



500 



(a.)=2-5cc. 



,3 



J UNE. 



„ v., 



500 



,, (mainly a. )=3cc. 



33 1-5 3) 33 

 „ IT, 



500 



(a.)=3-5cc. 



5 3 



500 



,, (a.)=3ce. 



33 



„ HI-, 



500 



(ly., 1 a.)=2cc. 





„ iv., 



500 





3 3 



„ v., 



500 



and Zoese, (1 y., 2 a., 3 Z.) 

 =2cc. 



July. 



„ III., 15-fm. Net, 



500 



(ly., la.,2Z.) 

 =l*5cc. 



55 



,, IV., Vertical Net, 



493 



,, (average size, 2'lmm.) and 

 7 Zoea3=l - 75cc. 









3 3 



„ V., 



485 



,, (average size, 2'lmm. ) and 

 15 Zoese^l'Scc. 









Nyctiphanes norvegica and Euchceta norvegica, though usually confined 

 to great depths, have been found by Murray t at the surface at certain 



* Found also in St. Andrew's Bay. Vide M'lntosh, Tenth Animal Report Fishery 

 Board for Scotland, Part III., p. 301. 



t Murray— "The Effects of Winds on the Distribution of Temperature in Sea and 

 Fresh- Water Lochs of the West of Scotland." Scottish Geographical Magazine, July 1888. 



