14 Mr. F. E. Beddard on the 
The only author who has seen, described, and figured the 
developing embryo of olosoma is Maggi*. ‘The egg,” 
he remarks (zbed. p. 15), “‘ up to the complete formation of the 
embryo is always covered by a very resistant membrane, 
which may be compared to an egg-shell.”” The ovum when 
deposited has no longer a spherical form, but is oblong, formed 
of an outer membrane (the “egg-shell”’), with an inner 
vitelline membrane, which surrounds the granular contents. 
As the embryo develops out of the ovum the red oil-globules 
appear, and at a comparatively early stage. The embryo 
can and does move freely about in the cavity of the shell. 
When hatched the sete are only just visible. The figures 
illustrating this description (tav. ii. fig. 11, A-F) show a 
progressive increase in size of the whole ovum, which is, when 
tully mature, very minute. The drawing of the embryo just 
before hatching measures a little more than 1 inch in length, 
and is magnified 700 times. 
Maggi speaks of the whole structure as an egg. Vej- 
dovsky +, however, says ‘‘ Nach Maggi sind die abgesetzten 
Cocons von Afolosoma elliptisch, durchsichtig, und die Embryo- 
nalentwicklung, &c.’’ He regards them as cocoons, and the 
resistant membrane figured and described by Maggi as the 
chitinous wall of the cocoon. It is rather surprising that 
Maggi did not arrive at the same conclusion, since he correctly 
described the clitellum, which is known to be the organ con- 
cerned with the formation of the cocoon. Possibly, however, 
the difference in shape which the supposed cocoon of Atolo- 
soma exhibits as compared with those of other Oligocheeta, 
led Maggi to the view that the membrane in question does 
not represent a cocoon. In all Oligocheta, so far as is known 
at present without a single exception, the cocoon, which 
varies in form, is invariably prolonged at either end into a 
longer or shorter process, particularly long in Criodrilus. 
Otherwise the cysts of Molosoma might well be supposed to 
be cocoons, even though they contain, according to Maggi, 
but a single embryo; for the Enchytraide and Naidomorpha, 
the nearest allies of Aolosoma, deposit only one ovum in each 
capsule. This fact was first discovered by the industrious 
investigator Jules d’Udekem {, and afterwards confirmed by 
Vejdovsky § and Stole ||. In the figure of the cocoon of 
* Unless there is any statement made in Stole’s paper. 
+ ‘System und Morph. d. Oligochaeten,’ p. 19. 
{ “Nouvelle Classification des Annélides sétigéres abranches,” Bull. 
Acad. Roy. Belg. t. xxii. 
§ ‘Monographie d. Enchytraeiden.’ 
\| ‘“‘PYispevky ku Studiu Naidomorph.,’ SB. Bohm. Ges. 1887, 
