269 Part IM.—Twenty-jifth Annual Report 
occur more frequently than the records of them would seem to indicate, 
for it is quite possible they may sometimes be included under the more 
general name of Enphausiide. The use of this less definite name is often 
rendered necessary owing to the disentegrated condition of the food, 
which, though perfect enough to show the relationship of the organisms 
composing it with the family referred to, are too incomplete to permit 
of the satisfactory identification of the species or even of the genus 
to which they belong. 
5th—Decapod larve. In the observations on the food of herrings 
given under each district. it will be observed that Decapod larve, though 
they may vccasionally be found in considerable numbers in a few of the 
stomachs examined, they do not appear to hold a very important place in 
the herrings’ bill of fare. Of the stomachs containing food examined for 
this paper, Decapod larve were observed in scarcely 34 per cent. of them, 
and the percentage of records for these larval forms in Brook and . 
Calderwood’s paper was even less. This infrequency of their occurrence 
in the stomachs of herrings, as compared with Calanus, can hardly be 
ascribed to the rarity of these organisms, for at times they are present in 
the sea in considerable numbers, as shown in plankton gatherings. It has 
to be remembered, however, that many of these larve are provided with 
a tough carapace and a spiny armature of a somewhat formidable 
character, which may tend to make herrings reluctant to attack them if 
other fuod of a more harmless kind be within reach. 
Some other forms, 7.e., Pseudocalunus, Centropages, Temora, &c., among 
the Copepoda, Evadne, as representing the Cladocera, Sayzttu, and other 
Annelida, and the eggs and scales of fishes have also been recorded, but 
they occur so very sparingly as to suggest that their presence with the 
other organisms in the stomachs may be due to their having been 
accidentally captured by the fish while in pursuit of other species. 
In dealing with a subject like this, it sometimes happens that a 
question emerges which, though not bearing directly upon it, is yet of 
interest because of its negative character. In studying the food of 
herring it soon becomes evident that Calanus, for some reason, forms an 
important part of it, and one likely reason, though it may not be the only 
one, is that this Copepod abounds everywhere throughout the wide area 
where herring fisheries are carried on. It has also been shown that the 
herring does not gather its food from the water merely by using its 
gills as a kind of seive, but hunts for and captures the organisms it lives 
on, and this seems to indicate that the fish may be able to some extent to 
discriminate between forms it prefers and those it dislikes, But though 
it may beable to do so, it is doubtful if it can distinguish differences that 
seperate closely-allied species, as, for example, between Calanus and 
Pseudocalanus, or between that species and Temora or Metridia, except 
that the Calanus is larger than the others. It is not surprising, therefore, 
to find that while the herring apparently prefers Calanus, other species 
should occasionally be present amongst its food, especially if they 
are moderately common. Keeping this in view, it is interesting to 
note that in the published accounts relating to the food of Clyde ani 
Loch Fyne herrings there is not, so far as I kuow, a single record of 
Hucheta norvegica having been observed amongst the foud contained 
in their stomachs. This Hucheta is now known to be generally common 
and at times abundant in Loch Fyne and it is moderately frequent 
in other portions of the Clyde area, but in none of the samples of Clyde 
herrings submitted for examination has Huchaeta been observed as part 
of their food. No doubt this Calanoid appears to be a true deep-water 
form, but it is also occasionally obtained amongst plankton collected 
. ihe “erie ee 
