TUBE OF PANTHALIS. 



333 



to the organs mentioned as visible in a dorsal view, the 

 second pair of parapodia, to which are attached special 

 and important fmictions, came into sight. These Hmbs 

 carry the first pair of elytra, and possess parts, equivalent 

 to those in succeeding parapodia, modified and adapted 

 to their work, which, as will be explained, is chiefly that 

 of forming the tube inhabited by the worm. Their ventral 

 cirri are much longer, and apparently stronger, than those 

 which follow ; their tips are semi-transparent, but for 

 the greater part of their length they are of an opaque 

 whitish colour (other ventral cirri are in parts of a 

 reddish tint) and being situate near the opening of the 

 mouth, have the appearance of buccal tentacles, or bristles, 

 which are usually directed forwards and downwards, the 

 tips almost meeting. The parts which correspond with 

 the ventral and dorsal lobes of other parapodia, are 

 modified in shape, and opaque white at their extremities ; 

 but these limbs are twisted downwards on their axes, so 

 that the portions which correspond to the dorsal lobes in 

 other parapodia, instead of being above, are in advance 

 of the ventral lobes. They are striking objects even to 

 the naked eye. The setae also differ, in that they are 

 chiefly long and straight or regularly curved, and although 

 some of them may be described as weak bristles, these 

 are spear-like in form, and devoid of the short terminal 

 "whip" or hair, which is characteristic of Panthalis. 

 The long curved setae, which issue from the cleft between 

 the lobes of the parapodia, are directed across the mouth 

 of the worm, and their object is probably to draw the 

 threads across, in the weaving process shortly to be des- 

 cribed. In this view, too, the outline of the front portion 

 of the body is noteworthy. At a distance of about — of 

 an inch from the extreme front, the dorsal integument, 

 which is here less covered by elytra than further on 



