182 DEVELOPMENT OF FISHES 
The eggs of Myxinoids are probably deposited at a 
single time; at first extruded by pressure of the body 
wall; then drawn out string-like, one egg following 
another, attached by hooked and thread-like processes 
(Figs. 186 A, 187A). Little is known, however, of the 
actual breeding habits of Myxinoids, either as to locality, 
mode, or season ; individuals of Myxine and Bdellostoma 
with ripe spawn have never been taken even in the 
most favourable regions. It is supposed that their spawn- — 
ing does not occur in the immediate neighbourhood of — 
the shore, since detached eggs have been dredged in the 
deeper water. Their breeding time is probably in the 
early spring, although possibly intermittent spawning 
takes place. In Myxine, according to Putnam,* the bulk 
of the eggs may be deposited as late as the beginning of 
winter. 
The spawning habits of Petromyzon, on the other hand, 
have been especially favourable for observation. The eggs 
are deposited in shallow and clear water and the move- 
ments of the fish may readily be followed. In the small 
stream at Princeton, for example, the lampreys make their 
appearance about the middle of May and remain on the 
spawning grounds two or three weeks. Their “nests” 
are seen scattered thickly on the gravelly shoals, often but 
a few feet apart. Each will be occupied by several males 
and a single female, the latter conspicuous on account of 
greater size. When spawning, the lampreys press together 
and cause a flurry in the water at the moment when the | 
eggs and milt are emitted. This portion of eggs will now 
* As observed at Grand Menan. Pro. Bost. Soc. Nat. Hist. Feb. 74. 
+ Professor McClure and Dr. O. S. Strong have here repeatedly observed 
the spawning lampreys; it is to their account that the writer is here indebted. 
Compare, also, the excellent account given recently by Professor Gage. 
Ref. p. 234. 
