386 HALOSYDNA GELATINOSA. 



immediately behind, and, from the rapid narrowing of the region, are thus nearer each 

 other. In an example of medium size from Bressay Sound in July the eyes were larger 

 than usual, and those of each side in contact. The lenses were also larger. The 

 reproductive elements did not appear to be much developed. Sir J. Dalyell mentions 

 that a large one, also from Shetland, had apparently only two eyes, but it is possible 

 they were confluent. In life the head is pinkish, and in the preparations iridescent. 

 In the majority the head is prettily mapped out by a pale median belt running forward 

 to the tentacle. The prominent lateral regions on which the eyes are situated are pale ; 

 while in front are two pinkish or brownish-pink smoothly rounded areas — indicating 

 the brain. The median tentacle is somewhat long and tapering, with a filiform tip. In 

 spirit it is slightly enlarged below the latter. The surface is quite smooth. The lateral 

 tentacles, the bases of which are lower than the median, are remarkable for their length, 

 being only a little shorter than the median, 1 and this is confirmatory of the nomenclature 

 adopted in the group. They are tinted brownish. The tentacular cirri agree with the 

 median tentacle in structure and length. The palpi are of moderate length, brownish, 

 tapering, and quite smooth. 



Body upwards of 2 inches, sometimes 3 J inches in length, slightly tapered in 

 front and much more distinctly tapered posteriorly ; rounded dorsally and flattened 

 ventrally. The dorsum is somewhat regularly banded across with greyish or greyish- 

 brown granular belts, and occasionally touches of white occur in the middle line of the 

 coloured belts. These alternate with a pale belt between the pedicles of the scales, 

 Between each pale belt there is thus a central band bordered with pale lines — extending 

 between the papilla on the cirrigerous foot, and a belt in front and behind, each of 

 which extends to the neighbouring segment. The segment-junction is, therefore, in the 

 middle of each band. No pale band occurs opposite the first pair of pedicles, but the 

 second and third, as well as the succeeding, have them. In some the pale belts are 

 more or less invaded by pigment. The caudal region behind the scales is continuously 

 grey. In front the nuchal collar forms a free flap, which is sometimes bifid and crenate, 

 but it is not papillose. The under surface is pale or slightly yellowish and iridescent. 

 The proboscis in many tints, the anterior region to about the sixth foot, the rest being 

 iridescent bluish with a red line in the centre. The segmental eminence is distinct, 

 and the papilla is evident at the fifth bristled foot, and continues to the posterior end 

 of the body. It is longest and largest about the beginning of the posterior third. 



The proboscis and digestive system differ from that of the previous genera in having 

 a muscular fold at each side in extrusion immediately below the angle, and divisible into 

 two halves, so that a doubly papillose aspect is given in certain views. Moreover all the 

 papillas at the tip of the extruded organ are more or less lobed. The six central are 

 large, and when viewed from the exterior do not differ very much from the ordinary 

 forms, except that they are more slender. On their inner aspect, however, they send off a 

 frill sloping towards the aperture. The succeeding eight on each side form a diminishing 

 series with frilled and lobed ends. The total number of papillas is thus twenty-two. 

 Each of the upper sharp horny jaws bites to the left of the corresponding ventral in 



1 Kinberg states that the antennaa are only about half the length of the palpi, and that the scales 

 are rugose. 



