EGGS AND LARV^ OF TELEOSTEANS. 105 



distance from the shore, but in this case are usually attached by the sucker to 

 floating pieces of sea-weed. The eggs are deposited in January and February, 

 and the young stages are to be found on the shore or in the tow-net through- 

 out the summer. It was observed by Mr Jackson, in the Southport Aquarium, 

 that the male parent, watching over the eggs, kept up a continual motion of his 

 pectoral fins in close proximity to the eggs, and it appears that this is neces- 

 sary to secure the sufficient oxygenation of the eggs, which are laid in such 

 large masses that the central ones might easily in still water be asphyxiated. 

 Young specimens of Cyclopterus were taken in the tow-net in the following 

 localities : — Surface, 30 miles north-east of May Island, July 17, 1885 ; surface, 

 near Inch Mickery, Aug. 26, 1885 ; surface, Firth of Forth, two occasions, 1884; 

 surface, east of Craig Waugh, May 1884. I have never taken any large 

 numbers either of these or any other fish larvae in the tow-nets. 



Species not identified. 



A certain number of well-marked species have been obtained by tow-net 

 collecting, which I have not yet been able to identify. There are two possible 

 methods of identifying an unknown species of pelagic ovum. One is to 

 compare it, or the larva hatched from it, with figures and descriptions of ova or 

 larvae already known; the other, to keep a number of specimens of the ovum 

 in question alive until they hatch, and then to keep the larvae till they attain 

 the specific characters of the adult fish. Both of these methods are liable to 

 error. 



Species No. 12 (PI. VII. fig. 2). 



This form is easily distinguished by one conspicuous characteristic, namely, 

 that the perivitelline space is very wide. The yolk is perfectly homogeneous 

 and transparent. The diameter of the vitelline membrane is 21 mm., of the 

 ovum 1 *2 mm. The eggs were obtained in the latter end of March, both in 

 1885 and 1886, about 10 miles east of the Isle of May. Unfortunately, time 

 could not be found to give sufficient attention to the form to isolate it and 

 keep it alive till hatching took place. Thus the characters of the larva were 

 not ascertained, and no egg at all similar has been taken directly from an 

 adult fish. 



Species No. 13 (PI. VII. figs. 3, 4). 



The eggs of this species were obtained in the tow-net, 16 miles beyond 

 the Isle of May, on April 30, and off Gullane Ness, May 27, 1886. The 

 diameter of the ovum, including the vitelline membrane, is "84 mm. The peri- 

 vitelline space is small; there is a single oil globule situated beneath the 



VOL. XXXIII. PART I. O 



