Fam.3, Plate 27. 



EOLIS AURANTIACA, Alder and Hancock. 



E. luteola, subrobusta ; branchiis robustis, tricoloribus, — infra purpureo-fulvis, medio albidis, supra 

 aurantiacis, — seriebus densis 10 — 11 digestis; tentaculis dorsalibus aurantiacis, corrugatis, tentaculis 

 labialibus breviusculis ; angulis anterioribus pedis obtusis. 



Eolis aurantiaca, Aid. and Hanc., in Ann. Nat. Hist,, v. 9, p. 34. 

 bellula, Loven, Index Moll. Scand., p. 8. ? 



Hab. Under stones near low-water mark, and in shallow water, Whitley and Cullercoats, North- 

 umberland, rather rare, A. H. Ardrossan, Ayrshire, rare; Fowey Harbour, Cornwall, frequent, J. A. 



Body about half an inch long, rather stout, tapering to a fine point behind, of a delicate 

 buff colour. Dorsal tentacles moderately long, tapering, a little wrinkled, of an orange flesh- 

 colour, a little paler above and below ; generally inclining forwards, their bases approximating. 

 Oral tentacles rather shorter than the superior pair, nearly colourless, linear, and slightly 

 flattened, with blunt points : they are set a little above the margin of the head, which is 

 produced laterally beyond their insertion. Branchiae numerous, placed along the sides of the 

 back in ten or eleven close, but well defined, transverse rows ; the anterior rows containing 

 five or six papillae each, the posterior, two to four. They are linear-oblong, and stout in 

 proportion to the length ; the upper portion is bright orange coloured, beneath which is a 

 belt of white, the remainder, varying from two thirds to three fourths of the entire length, is 

 of a warm purplish red, inclining to orange ; the colouring of the upper portion is exterior, 

 that of the lower proceeds from the central vessel, the margins of which are undulating, and 

 the surface indistinctly granular. Foot transparent white, produced, and slightly lobed in 

 front, tapering to a fine point behind. 



The colours of this species vary considerably, as well as the proportions in which they 

 are distributed on the branchiae ; sometimes the prevailing colour is much paler than here 

 described, but in south-country specimens it is generally brighter, the colour of the branchiae 

 frequently approaching to scarlet. On one occasion we obtained an individual with the 

 central vessel of the papillae of a warm yellowish olive. The tricoloured character of these 

 organs is prevalent throughout all the varieties; once or twice only have we found the 

 terminal orange portion indistinct or wanting. 



Foils aurantiaca, though by no means common, has been found in three widely distant 

 localities in this country, so that its range is pretty extensive ; and if, as we think, the Foils 

 bellula of Loven is a variety of this species, its distribution will be still further extended 

 in the European seas, M. Loven's specimens having been obtained on the coast of Norway. 



On the Northumberland Coast this species is usually found on Tichularice. The spawn 

 occurs in June and July ; it forms a broadish, circular, depressed belt ; in which the eggs are 

 divided into transverse masses, somewhat triangular in form. 



Figs. 1, 2, 3. Eolis aurantiaca, different views. 



4. Two of the papillae more highly magnified. 



5. Spawn. 



