SIGALION MATHILDA. 427 



At and below the spine are a series of bristles having stouter shafts, without spines at 

 the distal ends, and bearing shorter divisions to the terminal whip. The slender group at 

 the ventral border of the foot, that is below the inferior lobule, have in some cases one 

 or two spines at the end of the shaft, and long tapering and numerously (fifteen to 

 sixteen) jointed terminal regions, with a minute claw and secondary process at the tip 

 (Plate XLII, fig. 10). These bristles also lean to the two forms mentioned, and not to 

 Leanira. 



The ventral cirrus is long and subulate, reaching almost to the tip of the fleshy part 

 of the foot. It has an articulation at the extremity. 



Habits. — This species would seem to frequent sand in deep water, but it may yet be 

 found inshore. 



It is closely allied to Claparede's Sthenelais fuliginosa. 



Genus XXVI. — Sigalion, Audouin and M. Edwards, 1830. 



Head elongate from before backwards. Median tentacle absent ; lateral tentacles 

 short and papilliform, fixed to the anterior part of the cephalic lobe. Scales covering 

 the dorsum ; processes pinnate or with long papillae from the axis. The feet resemble 

 those of Sthenelais. Dorsal division clavate and furnished with a papilla. Bristles as 

 in Sthenelais. Ventral division somewhat truncate, and with a papilla internal to the 

 bristles, which are all bifid. Branchiae on every foot 1 (in S. Mathildse). Nerve-trunks 

 rounded in section, and the granular epidermic area enclosing them is expanded 

 inferiorly. Segmental eminence placed ventrally at the base of each foot. 



1. Sigalion Mathilda, Audouin and M. Edwards, 1834. 



Specific Characters. — Head elongate from before backward, with a truncate an- 

 terior border, having a slight peak at each side. Behind the border are two pairs of 

 small black eyes, the anterior nearer each other and larger. Body elongate (three 

 to five inches), little tapered anteriorly, and gradually diminishing posteriorly. 

 Segmental eminence situated ventrally at the base of each foot. Colour greyish- 

 brown or pinkish. Proboscis with seventeen to eighteen papillae on each lip. 

 Scales about sixty-four pairs, adherent, somewhat quadrate or rhomboidal, with 

 the posterior and inner corner rounded off. The processes along the external 

 border are pinnate, with long cylindrical papillae (about twenty on each side), 

 and at the base these are irregularly distributed around the central axis. Foot 

 with a club-shaped dorsal division, which has a single subulate papilla, and simple, 

 tapering, finely spinous bristles— increasing in strength externally. The inferior 



1 Cams, in his ' Prod. Fauna Metfit./ states that in the anterior part of the body the branchiae 

 alternate with the elytra, but that posteriorly they occur on all the feet. 



