AUTOLYTITS PROLIFER. 217 



1891. Autolytus Alexandri, Hornel. Trans. Liverp. Biol. Soc, vol. v, p. 245 (?). 

 1893. „ prolifer, Levinsen. Yidensk. Ud./' Hauchs/' p. 330. 



$ Bud. 

 1778. Scolopendrina marina, Slabber. Natuur. Yerlus., pp. 51 and 83, Taf. x, f. 3 — 5. 

 1855. Sacconereis helgolandica $ , Max Miiller. Arch. f. Anat., p. 14, Taf. ii, f. 4. 

 1865. „ „ De Quatrefages. Aimel., II, p. 74. 



1875. „ „ Mobius. Jabresb. Oomm. deutscli., p. 170. 



Habitat. — On shells and other debris procured by the deep-sea lines of the fishermen, 

 St. Andrews ; on stones near low water-mark (whence they are best procured by 

 immersion in sea-water, as they by-and-by crawl from the stones and growths thereon to 

 the margin of the water) ; it occurs also in tough translucent tubes under stones (gneiss) 

 between tide-marks in Bressay Sound, Shetland, where buds were found in July, 1871. 

 It may be a question whether it has not tubes at St. Andrews likewise, for it was generally 

 collected at the margin of a vessel into which stones from low water-mark had been placed. 

 Nurse-stock and buds were likewise found amongst tangle-roots in 8 fathoms in the same 

 region (Bressay Sound). 



Mediterranean. Atlantic. English Channel. North Sea. South Africa. Shores 

 of France. 



Head smoothly rounded in front; eyes placed closely together on each side, but 

 obliquely, so that the anterior are the wider apart, and they have a small lens. A long 

 tapering median tentacle, and two lateral. Two tentacular cirri occur on each side. All 

 these processes are more or less smooth. 



Body about half an inch in length, of a pale yellowish hue — somewhat darker in the 

 middle from the intestine, and with numerous small whitish specks over that. It is 

 slender, elongated, with numerous distinct segments, slightly and rather abruptly tapered 

 anteriorly ; more distinctly so posteriorly, where it ends in two slender cirri. The cirri 

 of the foot behind the tentacular cirri are considerably longer than the tentacular cirri. 



The proboscis in transverse section presents a radiate arrangement of fibres from 

 the firm inner lining to the outer coat. 



The foot (Plate LXXI, fig. 4) forms a bluntly-conical or rounded process with a 

 groove at the spine. The dorsal cirrus is comparatively short, the basal region or 

 cirrophore being of some size, and distinctly differentiated from the distal region. The 

 bristles (Plate LXXIX, figs. 23 and 23 a) are somewhat short, curved backward towards 

 the abrupt dilatation at the tip, and have a short terminal piece with two hooks, the 

 second being the larger. The dilated part of the shaft has minute spikes. A single 

 simple bristle is generally present in each foot, the tip being bent and diminished to a fine 

 point after the manner of Autolytus fallax, Malmgren. 1 



So far as present observations go, this form would seem to frequent the lower margin 

 of the tidal rocks, and probably also the laminarian region beyond, and from this to deep 

 water, so that the area for the production of buds is extensive. These buds ( J and ? ), 

 from their pelagic habits, scatter the reproductive elements very widely, and, as they occur 



1 ' Annul. Polycheeta/ p. 153, pi. vii, fig. 41. 



85 



