108 MR J. T. CUNNINGHAM ON THE 



Species No. 15, PI. VII. fig. 7. 



These ova formed a cylindrical rope-like mass, and were brought up on a 

 tow-net line from a depth of about 30 fathoms in the Gulf of Guinea. They 

 were obtained by Mr John Rattray, on two occasions when he was on board 

 the steamer " Buccaneer," a telegraph steamer placed at the disposal of Mr 

 J. Y. Buchanan, for hydrographical investigations. The first occasion was on 

 March 12 of the current year, in lat. 1° 17' N., long. 13° 56'6' W. ; the second 

 occasion was soon after, not far from the same locality. The depth of the 

 ocean at the place was 2725 fathoms. The felted filaments in the rope-like 

 mass were internal, the eggs external. Each ovum was 1 5 to 1 '6 mm. in diameter. 

 They are, as far as I am aware, the first Teleostean ova which have been found 

 to have a group of filamentous processes at each of two opposite poles of the 

 vitelline membrane. In these ova one group of processes is rudimentary and 

 functionless, but nevertheless the system of processes is closely similar to that 

 which occurs in Myxine (see my paper on " Reproductive Elements of Myxine 

 glutinosa," Quart. Jour. Micr. Set., 1886). Gobiidse, Blenniidae, Pomacentridse, 

 Atherinidge, Scombresocidse are the only families known in which processes of 

 the vitelline membrane occur, but it is impossible to say which of these families, 

 if any, includes the parent of the ova described. 



Identification of Ova. — The identification of the numerous pelagic ova which 

 are taken in the tow-net at the mouth of the Firth, at different times of the 

 year, cannot at present be carried out with complete certainty. If the eggs and 

 larvae of every species known to occur were adequately described and figured, 

 the feat might be possible ; but at present the identification of any egg taken 

 from the sea must always be subject to a certain degree of scepticism. I 

 have several times attempted to assign the eggs in a tow-net gathering each 

 to its parent species, and have satisfied myself that I had separated the 

 eggs of the Plaice, Cod, Haddock, PI. fiesus, and Trigla gurnardus. But 

 there may be other species with closer resemblances to these than I am at 

 present aware of. 



General Comparative Review of the Structure of the Ova and Larva? 



of Teleosteans* 



The method followed in the present section is to take the families of each 

 Order successively, and inquire what is known concerning the characters of 



* The classification employed in the present section is— 

 I. Physostonii. 

 II. Physoclisti. 



1. Anacanthini. 2. Acanthopterygii. 3. Acanthopt. Pharyngognathi. 



i. Lophohranchii. 5. Plectognathi. 



