66 W. O. MCINTOSH. 
round the blood-vessels, and with the cells somewhat regularly 
placed in rows, so as to form long loops, concentric or slightly 
radiate areas. The linear arrangement of these cells, indeed, 
is characteristic. The same regions are occupied by the large 
eggs in the female. The sexual elements were best developed 
in those obtained in July and August, both in Britain and in 
Norway, and they probably escape dorsally by the nephridia. 
Many ova occur amongst the branchie and bristles of the 
dorsum. In regard to the escape of these elements, the most 
likely channels appeared to be those that passed to the skin 
near the bristle-bundles. 
The ova in Spinther are proportionally as large as in 
Euphrosyne, but no nephridia have been observed, though it 
is possible they may yet be found. 
On Certain YounG Staces oF MAGELONA. 
The occurrence of several stages of the young of Magelona 
in the bottom trawl-like tow-net in St. Andrew’s Bay gives an 
opportunity for taking a brief survey of our knowledge of the 
subject. 
Claparéde, in 1863,! described some young stages of this 
species which he had procured at St. Vaast la Hougue in the 
summer of 1861. His youngest form was about 1 mm. in 
length, and cylindrical. The anterior end formed a wide 
funnel, and thus differed from any larve hitherto found at 
St. Andrews. The border of the funnel was beset with cilia, 
and cilia occurred behind it. Four reddish eyes occurred 
transversely on the dorsum of the head. Between the broad 
cephalic region and the first body-segment is an expanded 
region bearing a tuft of long cilia. There are from fifteen to 
twenty body-segments—which are widest anteriorly. From 
the projecting process of the first body-segment proceeds the 
tuft of long smooth bristles, which are almost as long as the 
body. The following segments had touches of brownish pig- 
ment, a pair of small hook-pads, and short bristles. Each 
1 «Beobachtungen iib. Anat. u. Entwicklungs. Wirb. Th.,’ p. 74, Taf. x, 
figs. 9—14, and Taf. xi, figs. 1, 2, 
