ARABELLA IRICOLOR. 399 



thicker than those beneath, and having a distinct cirrophore or enlargement at the base, 

 from which the cirrus comes off at a slight angle as it slopes outward, the tip in the 

 preparations being blunt. The ventral cirri are somewhat more slender than the dorsal 

 and a little shorter. By separating the sides of the vent the dorsal and ventral cirri of 

 each side are found to be attached to the same basal flap. The caudal segments would 

 appear to be frequently regenerated. 



Reproduction. — A dark-coloured specimen in a firm tube of small stones and shell- 

 fragments under a stone in a littoral pool at Herm in July was filled with ova, which 

 escaped apparently by pores (?) near the feet, especially towards the posterior half. 



Habits. — It is active and vigorous when stimulated, and is fond of twisting its body 

 into coils. It tinges spirit of a deep pinkish hue, then of a fine purple. In some instances 

 the animal is preserved in a firm spiral like a wire-spring. 



It is difficult to diagnose the precise form mentioned and figured by Donati l from 

 an Alcyonium in the Adriatic. It may be either this form or a Lumbriconereis. 



This is one of the striking British forms procured on the shores of Devon by the 

 indefatigable Col. Montagu, who in 1804 described an example as thick as a raven's 

 quill in diameter and 3 feet long. It is the Nereis iricolor of his MS. volume of drawings 

 (Plate XXXII, fig. 3, 1808) by his niece, Miss Dorville. 



In the illustrated edition of the 'Regne Anim.' (183G — 7) four striao are distinctly shown, 

 two stronger lateral, and two less marked on each side of the middle line of the dorsum. 



Grube (1840) gave this form only two eyes. 



There is some doubt as to whether Delle Chiaje's Lumbricus Saint Hilaire (1842) is 

 this species, for the four longitudinal series of spots, the two conspicuous eyes, and the 

 figure of the dental apparatus differ, yet it can hardly be anything else. 



The Lumbriconereis lonjissima of Grube 2 from Valparaiso is a form very nearly 

 related to this species, if it is not the same. 



The Aracoda coerulea of Schmarda 3 from the coast of Chili, Juan Fernandez, and other 

 localities, seems to be very closely allied, if not identical, the slight changes in the dentition 

 and other parts being probably due to variation, and these remarks are rendered more 

 probable by the perusal of the description and figures of Ehlers. 4 



Claparede (1868) associated Delle Chiaje's species with Grube's and subsequent 

 authors', and thought that the differences in coloration might be surmounted, some being 

 boldly marked with spots, others, as in those from the Channel Islands, being without 

 them. The very wide distribution of this form gives a margin for considerable variation. 



Ehlers (1868) points out that Grube in his original description mentioned only two 

 eyes, and omitted the dorsal cirrus. He also corrects the synonymy. 



The Notocirrus genicidatus of Claparede (1875), as described by Marion and 

 Bobretzky, 5 does not seem to differ materially from this species. 



1 ' Delia Stoi-ia Nat. Mar./ p. 60, Tav. viii, figs, g— k, 1750. 



3 f Annulat. CErsted in Naturhisfc. Foren. Vidensk. Meddel./ 1857, p. 158 (p. 1 sep. copy). 



3 < Xeue Wirb. Thiere/ ii, p. 115, 1861. 



4 ' Polychajt. Magell. u. Chilen./ 1901, p. 143, Taf. xix, figs. 1—6; and 'Zool. Jahrb./ snppl. 

 " Fauna Cliilen/' ii, 1901, p. 263. 



5 ' Ann. Sc. nat./ 6 e sei\, t. ii, p. 15, pi. i, fig. 2. 



