674 PROFESSOR W. C. M‘INTOSH AND MR E. E. PRINCE ON 
elongated and somewhat feeble herring cannot be confounded with the shorter and more 
vividly tinted larval sucker, which shoots into the surrounding water at once on issuing 
from the egg. The ova usually referred to this species, however, require further study, 
and the condition of the larva on emergence presents certain differences in the several 
varieties. It is possible that several species have similar ova, but where absolute 
certainty in regard to their determination was not possible, only those having the same 
size and structure were grouped under the head of this species. The spawning period 
ranges apparently from January to June. 
Cyclopterus lumpus.—The ova of this species are very variable in colour, ranging 
from a beautiful amethystine lustre through the various shades of straw-tint to greenish. 
The zona radiata is thick, and minutely punctured, but presents no special thickenings 
or superficial wrinkles, except where the facets of attachment are situated. The eggs are 
fixed together in sponge-like masses, so as to permit free aeration, yet the hatching of 
this species in confined tanks is somewhat difficult. The germ, as in pelagic forms, keeps 
for the most part at the lower pole, the oil-globules ascending to the upper pole. Their 
diameter is about ‘1 inch, while that of the large oil-globules is about ‘041 and less. 
Ova, apparently of this species, were obtained in great quantity from the stomachs 
of codling off Boarhills (Fifeshire), but, unless erroneously diagnosed, the gastric juice 
had caused a diminution in diameter, as they measured only ‘083 of an inch, while 
the large oil-globule in each measured ‘026, and one or two smaller globules were also 
present. Though to a slight extent digested, this ovam showed much resemblance to 
that of Cyclopterus, and formed masses of a yellowish green colour. In addition to the 
ordinary punctate structure, the zona agrees with that of Cottus in presenting larger, 
more evident dots at intervals (PI. I. fig. 24); indeed, this arrangement of larger punc- 
tures in the midst of the smaller ones is more distinct than in Cottus. They resemble 
large canals rather than radial strize, and they are finely dotted when viewed in profile, as 
at the edge of a torn fragment. It is noteworthy that at the same period as the above 
partially digested ova were obtained, a considerable quantity of similar eggs of a pale 
straw colour were procured on the beach near the Laboratory. Their diameter was ‘0916 
and that of the large oil-globule ‘031, and several smaller globules were also present. 
The ordinary pores were larger than in Cottus, but the larger pores, scattered at intervals, 
were similar. If these be the ova of Cyclopterus, which they closely resemble, consider- 
able latitude must be given in regard to diameter. It has, however, to be borne in mind 
that the condition of the ova (7.e., whether they had been subjected to dessication or other- 
wise) was unknown. ‘The spawning period of Cyclopterus extends from February to the 
end of May, and occasionally even a little later. 
Agonus cataphractus.—The ovaries of a number of female specimens caught by the 
sprat-nets in the estuary of the Tay were found to show nearly ripe eggs in December. 
The eggs are large, and of a dull golden or dull yellow colour, their diameter being ‘07 
inch and that of the oil-globule about ‘0216. The zonais minutely dotted with punctures 
arranged in a linear series. The surface is also covered with well-marked areole. (PI. I. 
