OPHELIA LIMACINA. 13 



Habits. — The only motions exhibited by the animal in confinement are slight 

 elongations and contractions, or curvatures caused by irritating it with a needle. At 

 intervals also the snout in front and behind the mouth is thrown into four longitudinal 

 grooves and ridges by contraction, both dorsally and ventrally. These do not affect the 

 smooth terminal cone and its slender papilla at the tip. Occasionally these contractions 

 of the snout would, from their regularity, appear to perform a special function — probably 

 connected with the driving forward of the tip in boring. On the whole it appears 

 to be sluggish, though its powerful ventral muscles must fit it for a considerable 

 amount of motion amongst the sand. When dislodged from the sand and tossed on the 

 beach no effort is made to bore, probably from exhaustion. Yet they live in sea-water 

 in confinement for weeks, although the pink hue of the two terminal ventral cirri soon 

 disappears. 



Reproduction. — On January 2nd the perivisceral space was crowded with small ova 

 — somewhat ovoid in outline. The males of Ophelia radiata, D. Ch., are distinguished by 

 their whitish colour, the females being greenish from the tint of the ova (Claparede). 

 The spawning period of this species is from October to July (Lo Bianco). 



A small example (Plate XCV, figs. 2 and 2a) about half an inch in length, dredged 

 in Valentia Harbour by Dr. Grwyn Jeffreys, in May, 1870, and which had well-developed 

 ova in the coelom, differed so much posteriorly from the ordinary examples, that it was 

 thought to be specifically distinct. Further examination, however, shows that it is a 

 young stage of 0. limacina. The head (Plate XCV, fig. 2) and the general shape of the 

 body agree with the latter, but the segments are less numerous (twenty-two or twenty- 

 three). The cirri commence in both on the same foot (eleventh), but the organs are 

 shorter and do not quite reach the tail. Moreover the latter differs in structure from the 

 ordinary form, for the tip of the tail (Plate XCV, fig. 2a) presents only a few blunt 

 papillae dorsally, and a rounded median, and two short lateral papilla? ventrally. When 

 viewed from the end this region shows a series of short, blunt papillae, about nine in 

 number, in the form of an arch over the large central and bluntly rounded papilla on the 

 ventral surface. One of the papillae forming the arch had a terminal sharp process or 

 papilla distally, but it is uncertain whether the others had such. It would, therefore, 

 appear that a considerable change takes place during the growth of this species in the 

 aspect of the caudal region, the two ventral processes, as the adult stage is reached, 

 assuming an elongated conical form with a probe-point, whilst the small papillae in the 

 young above these have now developed into conspicuous cirri. 



The Lumbricus radiatus of Delle Chiaje 1 (1825) indicates a form allied to Ophelia 

 limacina, but the want of accurate definition in the drawings leaves room for uncertainty. 



Milne Edwards (1834) inverted the animal, placing the head posteriorly with the 

 mouth as the vent. 



Audouin and Milne Edwards 3 thought that the Nais Horatii of Delle Chiaje 8 might 

 be an Ophelia, but there is dubiety on this head, both in description and figures. 



So far as (Ersted (1840) shows in his preliminary publication, Ophelia bicornis of 



1 ' Memorie degli Anim./ vol. ii, p. 414. Tav. xxix, fig. 1. 



2 'AnneL/p. 267. 



3 ' Memorie/ vol. ii, pp. 405 and 427, Tab. xxviii, figs. 20 and 21. 



