386 Miscellaneous. MISCELLANEOUS. On a Oicrious Phenomenon of Prefecundation observed in a Spionide Worm. By M. A. Giaed. The Annelide that forms the subject of this notice is a Spionide, the rather complicated synonymy of which may be stated as follows : — 8pio crenaticornis, Montagu ; Aonis Wagneri, Leuckart ; Colohran-clius ciliafus, Keferstein ; Uncinia ciliata, Quatrefages ; Scolecolepis vulgaris, Malmgren (pro parte). It has been found on the south coast of England, at Heligoland, at St. Yaast-la-Hougue, &c. It is common at Wimereux in a bed of shifting sand, where it lives in company with Magelona mirabilis, Echinocardium cordatum, Bathyporeia Rohertsoni, Carinella linearis, &c. Spio crenaticornis is very nearly allied to Spio bornhyx, Clapa-rede, of the Bay of Naples. The first fourteen setigerous segments present, at the base of each foot, sacs containing a coil of chitinous setse rolled up together. These organs, discovered by Claparede in Spio bombyx, and named by him "filieres," 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 " filieres " evidently seem to protect the Ann elide from the sand which presses upon on all sides; similar organs exist in the Magelonw 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 papillae. 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 ampullae exist, in variable numbers, in the ova of the Spionidse that I have examined, except those of the genus Magelona, which, moreover, differs in many respects from the typical Spionidse. With very weak carmine one can colour the ampullae, as was done by Claparede ; they fiU 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 caU them, as he does, protoplasmic spheres. I can only compare them to the foUicular 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-
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