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DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 85 
was procured, the posterior edge of the hypurals not being quite vertical; while the 
upward bend of the notochord is in the form of a gentle slope. 
Various stages were obtained on the 11th October in the same haul of the net, the 
earliest being like those last mentioned (1st October). The most advanced (about 19 or 
20 mm. in length) had well-marked dorsal and anal fins, vertical hypurals, and just a 
trace of a notochordal spike at the dorsal edge, and therefore intermediate between F 
and G (1st July). 
These remarks would tend to indicate that, at least, two spawning periods, as already 
known in regard to ova, occur in the neighbourhood. 
Some whitebait procured in the Thames in June measured from 38 to 40 mm., and 
presented most of the adult characters. These perhaps represent the young of a late 
autumnal brood, though, judging from those procured in St Andrews Bay in July, a close 
approach must be made by the winter broods, especially in the warmer southern waters. 
Meyer’s statistics would further corroborate this view. Similar Clupeoids abound in St 
Andrews Bay in March, and these may fairly be held to be the young of the previous 
season, According to MEYEr’s statistics, such would be about 5 months old, but probably 
they were from the ova of August, a period of seven months. 
The gradual change in the position of the anus, by the elongation of the region 
between it and the tail, is noteworthy, as also is the relative position of the fins in the 
young and in the adult. The latter, which has been called the migration of the dorsal 
forward, was pointed out clearly by SunpDEVALL and various subsequent writers, and 
appears to be characteristic of the Clupeide. The recent remarks of F. RarFaELE 
(No. 125a) on this subject are of much interest. 
Clupea sprattus, L.—About the beginning of May numerous transparent ova having 
a delicately reticulated yolk and somewhat thin zona radiata occurred in the bottom 
trawl-hke tow-net. They appear to be the same as HENsEN first found in the Baltic, and 
CUNNINGHAM obtained in the Firth of Forth west of Inchkeith, and which are described 
and figured by him. HeEnsen truly indicates the pelagic egg of the sprat as having a thin 
and transparent zona; while the larval form, he states, is distinguished from that of the 
herring by a slight flexure of the intestine.* Many are not quite round, their long 
diameter being ‘044 inch, and their short diameter ‘039. The reticulations of the yolk 
(Pl. I. fig. 5) are very fine, and much less distinct than indicated by Mr Cunnincuam, the 
margins of the sphere in an ordinary view presenting a confused series of lines. These 
eggs occur in very considerable numbers, and are evidently those of an abundant species. 
They are easily recognised from ova which resemble them in size by their translucency 
and the colourless embryo. They develop very quickly, and the larva soon escapes as a 
translucent form about 3°6 mm. in length, and, as Mr CunNINGHAM says, is at first devoid 
of pigment. It is a characteristic Clupeoid (Pl. II. fig. 13), with the anus situated 
posteriorly. The yolk has the same kind of reticulation as described above, and it is 
comparatively large. Well-marked sense-organs are present on the sides, the last pair 
* Funfter Bericht der Komission x. wiss. u. d. deutschen Meere, 1887, p. 40. 
VOL, XXXV. PART IIL. (NO. 19), 6R 
