TENCH. 
25 
compEirativG size of t'heir ventrcil fiiis^ wliicli in tlie male are 
far the largest, with a stout, thick, crooked, and transversely 
striated first ray. The bones also to which these fins are attached 
are large, thick, and extended even to the gill openings. 
Willoughby remarks, from Schenckfeld, that the Tench 
spawns at the time when wheat is in blossom. The spawn is 
shed at no great depth in the water, and the development of 
the grains is rapid, as they were traced by M. Rusconi in 
Muller’s “Archives,” for 1836; who observes that soon after 
the application of the milt the ovum loses its spherical form, and 
swells out into the form of a pear, and at the point where the 
swelling begins it is surrounded with a cluster of microscopic 
globules, which before were spread all over its surface. In 
half an hour the pear-shaped excrescence is divided into four 
globules, which in another quarter of an hour are subdivided 
into eight, and after a similar period into thirty-two, which still 
remain clustered together on the top of the egg. In another 
half hour more globules appear, which become less in size as 
they increase in numbers, and at length from their minuteness 
that part of the egg to which they are attached becomes almost 
as smooth as before they made their appearance. The embryo 
fish is now seen in the form of a whitish transparent speck, 
which is the rudiment of the backbone. The organization of 
the skin then proceeds, and the embryo as it is coiled round 
the yolk increases in length until the head becomes perceptible 
In forty hours from the first this embryo Tench gives signs of 
motion, and in further twelve hours it has freed itself from the 
skin of the egg; at which time the fish is two lines in length, 
and the blood is of its natural colour. For some hours after 
leaving the egg the young appear inert; lying on their sides 
and unable to swim; but when the swimming bladder becomes 
developed they assume their proper jiosition and activity. The 
intestines are not fully developed until seven days from leaving 
the egg; and then they begin to feed voraciously, but only on 
animal substances. 
The narrative here given may be considered as generally 
applicable to fishes of this family, and in its outline to fishes 
in general; since the variation is rather connected with the 
quickness of the development than the mere order of the pro- 
ceeding; and in regard to quickness it is much infiuenced by 
VOL. IV. b 
