ANGLER. 
141 
the interoperculal spine) is divided into three branches, 
the first advancing along the cheek, the second along 
the lower jaw, and the third in a posterior direction 
on the branchiostegal membrane, to the lower margin 
of the base of the pectoral tins. 
Thanks to the investigations of A. Agassiz", we 
now have complete information of the great changes 
which the form of the Angler undergoes during growth. 
O o O O 
Off Newport and in Massachusetts Bay (N. America), 
during the month of August, Agassiz found band- 
shaped, gelatinous masses floating at the surface, 2 or 
3 feet broad and from 25 to 30 feet long, of a light 
violet-gray colour, but covered with black dots arranged 
in one layer. The dots are the eggs, in which the 
black-coloured embryos are still enclosed (fig. 36, a). 
embryo is still enclosed in the membrane of the egg 
(fig. 36, a and b), the pectoral fins have begun to ap- 
pear, in the form of dermal flaps on the sides, behind 
the head; and on the back, vertically above them, a 
protuberance rises towards the dorsal edge. From this 
protuberance the first ray — which subsequently 
becomes the second — • of the dorsal fin soon rises; and 
simultaneously, as soon as the embryo has left the egg 
and before the yolk-sac is entirely absorbed (fig. 36, c), 
there appears on each side of the belly, below the base 
of the pectoral fin, a cauliform or somewhat clavate 
process, which is the rudiment of the first (outermost) 
soft ray in the ventral fin. This process, which for a 
time (fig. 37, g) is geniculate, grows longer and longer. 
On its inner side (fig. 37, c ) there appears the rudi- 
Fig. 38. Young of Lopliius piscatorius. u: with 4 rays in the dorsal fin and with the rudiments of the caudal fin ( + ); b: with 6 rays in 
the first dorsal fin, with heterocercal caudal fin, and with the second dorsal and the anal fins almost typical in form; c: the same specimen, 
seen from above and less powerfully magnified. After Al. Agassiz. 
In their first stages these embryos, or even the hatched 
fry, are scarcely recognisable as belonging to this spe- 
cies. The body is elongated, and the head no broader 
than in the ordinary fish-embryo. The embryonic fin- 
membranes of the dorsal and ventral edges — on the 
latter the membrane extends only behind the vent — 
are united at the end of the tail (diphycercal); and 
the comparatively thick notochord is almost perfectly 
straight all the way to this point. But even while the 
a Proc.’Amer. Acad., 1. c. Cf. also Baird, American Naturalis 
this exception, of the propagation of the Angler: we only know that 
of eggs in a gravid female 4 1 / 2 feet in length to be 1,427,344 (see 
the gelatinous mass found by him. 
ment of a new (inner) ray, and this new formation on 
the inner side is repeated once more during the growth 
of the rays. When the longest of them (fig. 38, b 
and c) is considerably longer than the whole body of 
the fish, the membrane of the ventral fins is also highly 
developed, and the rudiment of the outermost (first) 
ray in these fins (the spinous ray) begins to appear. 
Meanwhile the rays of the first dorsal fin (fig. 37, cl, 
e and / and fig. 38, a, b) also increase in the same 
;, vol. V (1871), p. 785. We have only very little information, with 
laics are rarer than females, and that Thompson estimated the number 
Day, 1. c.), while Baird calculated that there were at least 432,000 in 
