182 Part ITT —Siateenth Annual Report 
The total numbers of the monthly records exhibit a greater amount of 
divergence than those for the stations as shown by the next formula. 
Formula (2) shows the total number of records of Calanus for each 
of the stations for the seven years, (a) for the inner stations, I,, III., and 
IV. ; (0) for the outer stations, V., VIII., and IX. ; and (ce) for all the six 
stations :— 
Names of the Months, - da # I = S = Mew & 
ffs fe 65 43 cae 
; . ((@) the Inner Stations, - 20 27 15 32 25 14 16 14 7 22 21 27 
Oe tan # the Outer Stations, - 12 30 13 30 28 15 18 16 17 22 16 27 
Month, for —_{ (¢) all the Six Stations,- - 32 57 28 62 58 29 34 30 24 44 37 54 
Yet although there is a certain amount of variation, with the excep- 
tion of one or two months—as March and September—this variation 
is comparatively trifling, showing that Calanus was not only common, 
but also, on an average, very equally distributed throughout the estuary. 
The total number of records of this Copepod for the three inner and three 
outer stations, for the twelve months and for all the seven years, is 240 
and 244 respectively, or practically the same for the two groups of 
stations. Another point which may be noticed here, and which is shown 
in the Table, is that the totals of the monthly records for the seven years 
and for each of the six stations for April are, with one exception, exactly 
alike—the number for April for each station being ten, except at Station 
I., where the number is twelve. It would also appear from the tabular 
enumeration of the records that during six out of the seven years 
(excluding 1889) Calanus was more common and generally diffused 
throughout the district referred to here, in the month of April, than in 
any of the other months. The reason for this uniformity may not be 
easily explained. It may be due to a periodic migration of Calanus, or 
to some influence inducing them to crowd more in towards the shore at 
this season—probably for spawning. 
Formula (3) shows the total number of records of Calanus for each of 
the seven years, (a) for the inner stations, I., III, and IV.; (0) for the 
outer stations, V., VIII., and IX.; and (c) for all the six stations :— 
Numbers of the Years, - - - - 1889. 1890. 1891. 1892. 1893. 1894. 1895. 
Total number of ((@) the Inner Stations, 15 48 49 45 42 20 26 
Records for each 
Year, for 
(6) the Outer Stations, 19 43 48 49 44 14). 27 
(c) all the Six Stations, 34 86 97 94 86 34 88 
The greatest difference between the yearly totals for the inner and 
outer stations is that for 1894, while the total number for the seven 
years for each group of stations shows only a difference of four—the 
numbers being for the inner stations 240 and for the outer stations 244. 
But though Calanus finmarchicus is the most common Copepod in the 
Firth of Forth, there are one or two other species included in the lists of 
tow-net gatherings which are more or less generally distributed, and at 
times moderately frequent, and which no doubt compete closely 
with Calanus as important sources of fish-food, especially as the food of 
young fishes. Temora longicornis is one of these; so also, though in a 
somewhat less degree, are one or two species of Acartia—viz., A. 
longiremis and A. claus (both of which are found in the Forth estuary). 
I do not propose to refer at length to the distribution of these Copepods, 
as the Tables which follow show by comparison with that of Calanus 
its more important details, as well as some other of the more noticeable 
differences in this respect between them and that species. 
