46 rRELI.MIXAIJY NOTES ON THE RErRODUi 'TION OF TELEOSTEAN 



However, a certain number of ova were impregnated, but while 

 several survived up to a late stage of development, only one hatched. 



The unfertilized ova immediately after extrusion were found to 

 measure from "92 to "93 mm. in diameter. After fertilization, ova 

 measured during the progress of development varied from "90 to "99 

 mm. The single oil-globule measured from '16 to "18 mm. In the early 

 condition the globule exhibited a distinct yellow or greenish yellow 

 colour, a trace of which remained almost up to the time of hatching. 



Sixty-six hours after fertilization the embryo had a free tail equal in 

 length to the head and trunk. Pigment was present in the form of 

 small black chromatophores rather profusely distributed over the 

 embryo, except at the extremity of the tail, and more sparsely over 

 the yolk. Pale yellow pigment was present on the embryo, imparting a 

 uniform yellow tinge, the individual chromatophores not being visible 

 under a moderately high power. Tlie epidermis was beset with a not 

 very conspicuous reticulation of minute papillae. 



Ninety hours after fertilization a single larva had hatched ; it 

 measured 2-38 mm. in total length, the marginal anus 1'07 mm. from 

 the snout, being slightly anterior to median. The rectum was 

 distinctly separate from the yolk. Yellow pigment was present on 

 all parts of the larva (except the end of the tail), but in greatest 

 abundance, in so far as concerns those parts, along the dorsal and 

 ventral regions of the head, trunk, and tail. On the marginal fins and 

 yolk-sac it was present in scattered dendritic chromatophores, rather 

 more abundantly on the fins of the posterior half of the tail than 

 anteriorly. Small black chromatophores occurred sparsely over the 

 entire general surface, more diffusely on the posterior part of the tail 

 (not fins) than at any other point, but on the dorsal fin were confiued 

 to the immediate neighbourhood of the margin. A small pectoral fin 

 was observable, and opposite to this was a slight inflection of the 

 margin of the dorsal fin, which latter commenced to rise, as is usual 

 in newly-hatched larvse, near the level of the hind end of the otocyst. 

 The oil-globule was posterior in position. The epidermis was beset with 

 minute papillio or tubercles, with some indication of connecting ridges 

 or stria3. 



The larva did not survive to exhibit any more advanced stage of 

 development, and none of the remaining eggs hatched. 



I am in some doubt as to whether this observation of the early stages 

 of ]\ unimandatus throws any light on previously known but unde- 

 termined ova and larvre. The form that at once suggests itself in this 

 connection is the Species F of Mcintosh and Prince, which has also been 

 described by myself {Trans. R. Diib. Soc, s. ii., v. pt. ii. p. 101), and has 

 more recently been recognised by Ehrenbaum at Heligoland (Me?- u. 



