286 MR, E. W. I. HOLT ON THE [Apr. 19, 



as Stolzmann considers in birds ', by ovarian nutrition, it is obvious 

 that the conditions are decidedly adverse to a preponderance of 

 female offspring. Among insects it is known that sex is, or in 

 some cases may be, determined by the nutrition of the larva. It 

 is difficult to believe that this is the case in Teleostean fishes, 

 since we might expect that the female sex would invariably 

 preponderate in size and number. Valuable information might 

 accrue from the experimental feeding of salmon or trout larva3 ; 

 our present control of marine forms, and especially of such as 

 propagate by minute pelagic eggs, does not promise much in this 

 field of research. 



Although the subject does not concern the sexual dimorphism, 

 a few words are necessary on the position of the eyes in order to 

 explain my figures. In dead specimens the eyes are sunk into the 

 sockets and scarcely project above the general level of the top of 

 the head. They are faithfully presented in such condition in 

 all the figures of 0. hjra which I have seen. In life, however, the 

 ej'es project boldly above the cephalic contour as indicated in my 

 figure 1 '". They are not retracted on alarm, but only Mhen the 

 fish has buried itself in the sand or gravel. Retraction is evidently 

 effected by the eye-muscles. Protraction must be ascribed to the 

 elasticity of the membranous wall of the orbit and of a large but 

 very delicate recessus orhitalis \ This structure communicates with 

 the membranous cavity, as may be demonstrated by injections, 

 below the centre of the eye. It is so thin-walled that I have not 

 found it possible to make satisfactory dissections. Lying for the 

 most part immediately under the skin, externally to the eye, it 

 dips anteriorly below the spatulate part of the great lachrymal 

 scute. Posteriorly it approaches the base of the preopercular 

 trident. In its lateral region it appears broken up into a great 

 number of minute chambers into which the injected fluid does not 

 readily pass. I must acknowledge the assistance of my friend 

 Mr. L. W. Byrne in tracing out this organ. At present our 

 results do not justify a more detailed description. 



III. Courtship and Pairing. 



The Dragonets inhabit a glass-fronted tank, about four feet 

 deep, on the south side of the aquarium. The sides are painted 

 white and the bottom is covered with fine light gravel. 



The other inhabitants of the tank are a number of grey mullet, 

 two red mullet, a small bass, some rockling, and sundry crabs and 

 hermits, the latter with their associated anemones, Adamsia 

 rondeletii and A. ■palliata. 



In February there were two large male Dragonets, with f ully- 



^ I tQust acknowledge my indebtedness to Mr. F. E. Beddard's ' Animal 

 Coloration,' Lond., 1892, p. 277, &c. 



* Probably some approacli to the natural condition is shown by Eiehardson, 

 in his figure of C. reevesii (C. longicaudatus, Temm. & Schleg.) in Voy. Sulph., 

 Fish, pi. 36. fig. 1. 



5 Cf. P. Z. S. 1S94, p. 422. 



