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 ovum 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 striae, 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 (i.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 zona is minutely dotted with punctures 

 arranged in a linear series. The surface is also covered with well-marked areolae. (PI. I. 



