of the Fishery Board for Scotland. 
349 
IX.— SOME FEATURES IN THE EGG AND LARVA OF THE 
SKULPIN {CaUionymus h/ra). By Professor E. E. Prince, 
B.A., F.L.S. (Plate XIII 'figs. 10-13.) 
When the eggs of the skulpin or dragonet were described for the first 
time by Professor M'Intosh in 1885, they were at once seen to exhibit 
features of an unusually striking character. No other egg was known to 
show the remarkable external reticulation seen upon the surface of the 
dragonet's ovum. Since the eggs were discovered at St Andrews they have 
been obtained by various observers — by Mr J. T. Cunningham at Plymouth 
and Millport, and Mr Holt off the west coast of Ireland ; but the several 
published notices of this unique type still leave some points of interest 
undescribed. Some examples have been identified recently in a series of 
pelagic ova collected in the scientific cruises of the ' Garland,' and a 
number have been secured during this summer and last in St Andrews 
Bay. A further account, therefore, of undescribed stages in the develop- 
ment of this species may not be without interest. Until Mr Holt hatched 
some ova last year the embryo of the dragonet was unknown, though 
Professor M'Intosh had obtained somewhat advanced larval forms (about 
3 mm. in length), of which descriptions have been published, and had 
traced the post-larval stages up to the attainment of the adult features. 
Examples of developing ova secured in the bay were examined in the 
Marine Laboratory, St Andrews, on May 22. They showed the embryo 
in an early condition, possibly two or three days after fertilisation (Plate 
XIII. fig. 11). On account of the characteristic reticulation of the capsule 
the ovum has a certain opacity, rendering it discernible without difficulty 
in still water. The external reticulation has been described with some 
fullness ; but since Raffaele has published an account of the minute pelagic 
egg of Uranoscopus scaber, and List has described the floating egg of 
Cremlabrus tinea, both distinguished by an external reticulation of 
perfectly regular hexagons, it is necessary to point out that the figures 
upon the surface of the dragonet's ovum are by no means regular nor of 
one geometrical type. The figures assumed by the projecting network are 
for the most part hexagonal, but pentagons and octagons are frequent. 
The sides, moreover, of these polygons are of varying length, two or three 
sides being occasionally so elongated as to produce a very unsymmetrical 
outline and at their angles small irregular interspaces occur. Further, 
a pentagon or hexagon may extend over an area four or five times 
greater than that of one adjacent. Notwithstanding such irregularities 
and variations, apparent upon minute examination, the appearance of 
the external markings is that of an elegant honey-comb pattern. 
The eggs studied on May 22 were at different stages of development. 
In the youngest, apparently about the second or third day after fertilisa- 
tion, Kupffer's vesicle was fully formed, and in one example the structure 
was compound, its periblastic envelope including a smaller, as well as a 
somewhat enlarged, spherical chamber. The optic outgrowths were 
defined, but the lenses were undeveloped, while the myotomes were out- 
lined along the whole length of the embryo, the trunk at this time 
encircling about half the circumference of the yolk. The notochord was 
breaking up into flattened discs, but the alimentary tract was, so far 
as could be seen in the living egg, not differentiated. The yolk 
showed very remarkable features (Plate XIII. fig. 1 1 ). Its cortical portion 
was broken up into large ill-defined masses, forming a thick superficial 
