A Summer Afternoon by the Sea. 155 



are two pairs, of which, the anterior (b) may be considered an- 

 tennae, and the posterior (c) tentacular cirri ; but these distinc- 

 tions are perhaps somewhat arbitrary, and are rather convenient 

 than precise. The antennae (fig. 3) consist of a marginal por- 

 tion, thick and cord-like, of granular tissue, of which the an- 

 terior is thicker than the posterior edge, and a thin clear 

 membranous portion stretched across. The latter seems double, 

 and to inclose a cavity filled with fluid • for I observed eddies 

 of minute corpuscles, which were accelerated whenever they 

 approached the cord-like margins. 



The second pair, or cirri (c), have a similar structure, but 

 the front cord is prolonged into a stiff straight seta of a length 

 superior to that of the body and tail, which points obliquely 

 backward, and is capable of but a very slight change of direction, 

 by a contraction of the hinder part of its base. This pair is 

 probably the seat of a delicate sense of touch. 



Immediately between the bases of the cirri are seated the 

 two eyes (cZ) ; each consisting of a distinct lens,* very convex, 

 seated on a much larger mass of black pigment, and looking 

 outward laterally, and the whole eye inclosed in, or resting on, 

 a globose body of translucent tissue, probably a nervous gan- 

 glion, which is in contact with its fellow (see fig. 2). I did 

 not remark any movement in the eyes. 



Yiewed from beneath, the cavity of the mouth is seen to 

 open just under the eyes (e), the aperture being formed by an 

 irregular corrugation of the surrounding flesh, forming lobes. 

 In one of my Ilfracombe specimens, I was so fortunate as to 

 see the protrusion of a thick oesophageal proboscis to some dis- 

 tance, of an ob-conic form, or somewhat trumpet-like, with a 

 large four-sided orifice obliquely terminal. This observation 

 was the more important, as such a protrusile oesophagus is emi- 

 nently characteristic of the Annelida, and does not seem to 

 have been seen in this animal by any other observer. In my 

 recent specimen, the oesophagus (/), when withdrawn, reached 

 to the second pair of fins, where, after a constriction, if ex- 

 panded into an alimentary canal (g), having distinct corrugated 

 walls, whose outline wa> commensurate with that of the body 

 cavity, with a slight tendency to enter into the bases of each 

 pair of fins. The cardiac extremity of this viscus, during my 

 examination, was insensibly pushed forward, so as to inclose 

 the termination of the oesophagus, but not changing the position 

 or the appearance of the latter. It was manifestly empty. f 



* MM. Carpenter and Claparede state (and quote the testimony of MM. 

 Leuckhart and Pagenstecker to the same point), that the lens in each eye is double. 

 It, however, appeared to me manifestly single. 



f The alimentary caual in one specimen obtained by MM. Carpenter and 

 Claparede contained fragments of a Beroe, which were kept in active motion by 

 their own cilia. 



