402 PANTHALIS CERSTEDI. 



Proboscis (Plate XXXIV, figs. 3 and 4) exsertile, cylindrical, famished with yf 

 papillge, the median — upper and lower— longer, especially the superior. In the British 

 forms it projects from the mouth like a tentacle, and tapers from base to apex. The 

 inferior, also conical, is much less, and has an inwardly projecting hood or arch at its 

 base. The four maxillse are elongate, brownish, strongly hooked at the tip, which is 

 a process of the dorsal rib, and with an attached flat blade, the inner edge of which has 

 six teeth (Kinberg says six to eight teeth, while Marenzeller shows in his figure traces 

 of six). 



Xo pregastric cseca occur, and in this respect it agrees with the Sigalionidae. The 

 stomach is very muscular. The lateral intestinal ca3ca are large and elliptical, with a 

 narrow neck. 



Scales (Plate XXXIV, fig. 5) thirty-nine pairs (Kinberg), in life pearly white, 

 semi-transparent, the first three pairs flattened, covering the dorsum, the rest cam- 

 panulate, and about one-third the breadth of the dorsum on either side, the centre being 

 bare. "During life these do not rest upon the body, but in front are tilted up, so as to 

 meet at an angle above the prostomium, the last few pairs of elytra also assuming a 

 similar position. ... A constant rising and falling of the elytra, as though to 

 facilitate the passage of water for the purpose of respiration, was observable" 

 (Arnold Watson). They are perfectly smooth, of fair thickness, and richly supplied 

 with nerve-trunks, as in the PolynoidaB. Mr. Watson found in a living example that 

 posteriorly the last two pairs only met in the middle line, whereas in a specimen 

 in the British Museum, dredged by Sir John Murray in 44 fathoms, the last six pairs 

 did so. 



Feet. — The dorsal division of the first foot bears two long and rather slender spines, 

 and several long slender bristles, finely spinous from a short distance above the base to 

 their capillary extremities. The slenderness of these hairs is in contrast with the con- 

 dition of the homologous organs in the Polynoidas. The spines are minute. 



The second foot is somewhat complex, and is specially interesting in connection with 

 the action of the parts in the formation of the tube, as recently described by Mr. Arnold 

 Watson. The foot is essentially bilobed, — that is, divided primarily into a dorsal and a 

 ventral division, the latter, it is true, being again subdivided. The dorsal division has 

 its spine, and forms an even ridge dorsally — terminating in a projecting globular or clavate 

 knob — directed downwards and projecting as far as the ventral division. Beneath are a 

 series of stiff bristles of the type seen in the foregoing process, but much stronger. They 

 taper from the base to the slender apex, and the short but distinct spines begin a little 

 above the former. The main ventral division is trilobed. The uppermost bristles 

 spring rather above the lobe, point upwards and outwards, and have stout shafts ending 

 in a spinous region dilated at the base and tapering to a slender tip. As we proceed 

 downwards the spinous region becomes more slender and tapering — the enlargement at 

 the base of the region gradually diminishing, and the shafts also becoming more slender. 

 An accessory lobe (bract) occurs at the ventral border, and in it the bristles, though 

 retaining the same type, become more slender, and the tapering spinous region shorter. 

 The ventral cirrus of this foot agrees with the homologous organ in the Polynoidse, and 

 is apparently used in the same manner. Though certain modifications exist in this foot, 



