DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 673 



of the germ, the general size being about 3^ inch. Towards the period of hatching 

 the chitinous zona radiata is more easily torn, and readity splits into lamellae, all of 

 which show minute punctures (PL XX. fig. 8), appearing like minute pale specks on 

 a dark ground. In some again the punctures are lost in a general granular area. 

 Whether these so-called punctures were actual canals, or only radiating striae, could not 

 be demonstrated. 



This separability of the capsule into layers in the later stages does not conflict with 

 the view that it is really a single coat. Such chitinous formations in other forms show 

 the same tendency to split into filmy strata under certain circumstances, and, as explained, 

 a like tendency is exhibited in the extremely thin zona radiata of Gadus morrhua 

 and G. ceglefinus. In size the ovum of Anarrhichas* resembles that of the salmon 

 (PI. XX. figs. 9, 10), though the punctures in the latter form (fig. 11) seem to be 

 somewhat larger. 



Liparis montagui. — The capsule presents externally a minutely areolate appearance 

 (PL I. fig. 4) due to slight elevations, resembling indeed the surface of grained morocco 

 leather, the elevations having a more or less marked linear disposition. In newly 

 deposited examples, or in ripe ovarian ova, the external configuration shows an almost 

 regular hexagonal character (PL I. figs. 21, 22), the sutures being pale, while the central 

 regions are more opaque, probably from increased thickness. After exposure to water a 

 change seems to occur, the hexagonal facets becoming less marked, while a series of eleva- 

 tions become visible, and are apparently due, therefore, to a later modification. In 

 oblique views the capsule shows undulating surface-markings (PL I. fig. 22). As these 

 ova were not actually observed to be deposited by this species, however, it must be added 

 that a margin of doubt exists as to the feature described. 



In this as in other species the zona radiata is at first soft and pliant, hardening 

 subsequently, as in those deposited in the Laboratory. In the fresh condition minute 

 punctures are visible, though these are less distinctly seen after mounting in certain 

 media, e.g., Farrant's solution, and on tearing the capsule the same dense series of laminae 

 can be separated as in Anarrhichas and Cottus. While in the ovary the eggs have a pale 

 straw colour, and measure about '043 inch, the oil-globule being *0083 or less, but those 

 just deposited in the tanks show a slight increase in size, viz., "045 inch in diameter, 

 and the oil-globule varies from *005 to '0116 of an inch. The eggs of this species are 

 very frequent on sea-w T eeds, zoophytes, and fragments of sticks and debris at the bottom, in 

 comparatively shallow water as well as in the deeper parts, and they show much variation 

 in colour, from pale straw to a light pink or flesh colour. They have often been mistaken 

 for the eggs of the herring, from which they differ in regard to the structure of the 

 zona radiata, and in the absence of the so-called vitelline membrane, which Mr Brook, 

 however, says is not present. The embryos again are sufficiently diagnostic, for the 



* It is remarkable that the masses of the eggs of this species have hitherto escaped observation, fishermen being so 

 little acquainted with them that they were mistaken for those of the salmon. Some time afterwards the recently 

 hatched embryos (then unknown) were recognised by one of us in Edinburgh, having been forwarded to the Fishery 

 Board for Scotland by one of the steam trawlers of the General Fishing Company, Granton. 



VOL. XXXV. PART III. (NO. 19). 5 R 



