1915] ICHTHYOLOGICAL NOTES 109 
ICHTHYOEOGICAL, NOTES: ON: 
I. OPHIODON ELONGATUS GIRARD; 
Il. ONCORHYNCHUS KETA WALBAUM; 
III. THE DIAGNOSIS OF FISH BY MEANS OF THE SCALES; 
IV. MALLOTUS VILLOSUS MULLER. 
By C. McLEAN FRASER, Pu.D., 
Curator of the Marine Biological Station, Nanaimo, B.C. 
I. OPHIODON ELONGATUS GIRARD. 
Plate X, figs. 21-25 
Fishes in general pay little attention to the well-being of their pro- 
geny. In oviparous forms the eggs are shed, provision is made for 
fertilisation and that is the end of it as far as the parent is concerned, 
Among the exceptions to the general rule is Ophiodon elongatus. 
commonly known as the Blue or Green Cod. The eggs of this species are 
very adhesive so that after they are shed they are collected into a large 
mass which becomes attached to a rock, usually in a crevice or some 
-other unevenness, a short distance below low water or occasionally in 
such a position that they may be exposed during a low spring tide. Over 
the mass the parent fish keeps guard so well that no intruder has much 
chance of meddling. In no case have I found the female engaged in 
this protective duty, but if she does not take any part, the male must 
have a weary vigil, as the period of incubation is about two months. 
In the first instance my attention was directed rather forcibly to 
this characteristic of the Blue Cod. While collecting at low tide near 
the Biological Station, Departure Bay, I saw a mass of eggs under a 
rock about a foot and a half below the surface of the water. Wishing 
to examine some of them I managed to force off a small bunch with 
the blade of an oar—they stick so solidly together that this is not an 
easy matter—immediately after which I put down a dip net to catch 
them before they would sink to the bottom and was somewhat sur- 
prised with a sudden jerk that almost took the dip net out of my hand. 
A little later I discovered that the jerk came from a large cod that ap- 
peared from under the rock to resent the intrusion. When I thought 
of the sharp teeth of Ophiodon I was much better satisfied that the net 
rather than my hand received the force of the attack. The satisfaction 
was by no means decreased when further experiment showed how 
savagely he could attack starfish, nudibranchs, etc., that were lowered 
