386 Miscellaneous. 
MISCELLANEOUS. 
On a Curious Phenomenon of Prefecundation observed in a 
Spionide Worm. By M. A. Grarp. 
Tur Annelide that forms the subject of this notice is a Spionide, 
therather complicated synonymy of which may be stated as follows :— 
Spio crenaticornis, Montagu ; Aonis Wagnert, Leuckart ; Colobran- 
chus ciliatus, Keferstein ; Uncinia ciliata, Quatrefages ; Scolecolepis 
vulgaris, Malmgren (pro parte). 
It has been found on the south coast of England, at Heligoland, 
at St. Vaast-la-Hougue, &e. It is common at Wimereux in a bed 
of shifting sand, where it lives in company with Magelona mirabilis, 
Echinocardium cordatum, Bathyporera Robertsonr, Carinella linearis, 
&e. Spio crenaticornis is very nearly allied to Spio bombyx, Clapa- 
réde, of the Bay of Naples. The first fourteen setigerous segments 
present, at the base of each foot, sacs containing a coil of chitinous 
sete rolled up together. These organs, discovered by Claparéde in 
Spio bombyx, and named by him “ filicres,” should be sought for in 
the other Spiones. Their presence would furnish a good character 
for the generic distinction of Spio and Nerine, which are so fre- 
quently confounded. ‘The “‘ filicres” evidently seem to protect the 
Annelide from thesand which presses upon on all sides; similar organs 
exist in the Magelone in the posterior part of the body beyond the 
ninth segment. 
The mature ovum of Spio crenaticornis has the form of a spheroid 
strongly flattened at the two poles. The equator is ornamented 
with about twenty transparent vesicles, arranged like a circlet of 
beads at the periphery of the greyish vitellus. These vesicles 
belong to the capsule, which is very thick and sprinkled with 
papille. This is shown by the action of picrocarmine ; the vitellus 
contracting, each vesicle escapes from the vitelline mass, and assumes 
the appearance of a small hyaline phial suspended from the capsule 
by a slender neck. Similar ampulle exist, in variable numbers, 
in the ova of the Spionide that I have examined, except those of the 
genus Magelona, which, moreover, differs in many respects from 
the typical Spionide. With very weak carmine one can colour the 
ampulle, as was done by Claparede; they fill through the uncon- 
tracted neck. It is very evident that these elements have nothing 
to do with the formation of the blastoderm, contrary to the opinion 
of the illustrious zoologist just mentioned. Nor can we call them, 
as he does, protoplasmic spheres. I can only compare them to the 
follicular elements of the capsule in the Ascidia. Their physiological 
function is perhaps that of micropyles. 
The germinal vesicle is very large ; its radius is about one third 
of the equatorial radius of the ovum. Its contour is not at all well 
defined in the fresh ovum ; the employment of picrocarmine renders ~ 
it more distinct. The nucleolus is very bright and voluminous. Its 
position is strictly central. 
Some time before the maturation of the ovum we see in the ger- 
