iralty Marine Laboratory^ St. Andreivs. 293 



very prominent in the posterior part of the body, and 

 the segmental organs indicated. The dorsal cirri resemble 

 the tentacular ciiri, and extend nearly to the tips of the 

 bristles. 



It is an interesting fact in the history of this genus that 

 one species from the Antarctic seas resides in a tube formed 

 by the branches of a coral, the tough nature of the reticulated 

 walls of the tube thus making an ( fficient protection for the 

 elongated annelid. The twigs of the coral seem to adapt 

 themselves to the tunnel of the worm. 



Prcegeria remota. Southern, one of the Pisiouidse, was 

 dredged on the west coast of Ireland [Soutliern). Southern 

 agrees with Ehlers that Preefferia most nearly approaches the 

 Aphroditidse, resembling the Sigalionidae "in the reduction 

 of the head and its appendages, the forward position of the 

 buccal segment, the shape of the compound setse, and the 

 presence of jaws." " I am of opinion that the elongate 

 ventral anterior cirri of the Pisionidae are homologous to the 

 palps of the Sigalioniuse, that the slender dorsal and globular 

 median cirri, together with the. swollen bases which contain 

 the prominent spines, constitute the parapodia and cirri 

 o-f the buccal segment, the whole being homologous to the 

 segment bearing tentacular cirri in Pholoe and the first 

 setigerous segment in Sthenelais. The first setigerous 

 segment in the Pisionidaj would then be homologous to the 

 first setigerous segment in Fliolue and to the second in 

 Sthenelais. In all three cases the ventral cirrus of this seg- 

 ment is elongate and functions as a tentacular cirrus, a 

 remarkable resemblance, which is best explained by the 

 theory of close relationship.'^ 



Whilst these views are full of interest, it has to be added 

 that no known Sigalionid, or other allied form, shows any- 

 thing approaching the condition in the cephalic region of 

 Progeria with its remarkable spines, though the proboscis, 

 its circlet of papillae, and its jaws have a near resemblance to 

 those in the Polynoidte and allied forms. The length of the 

 feet and the proportionally great size of the bi'istles, which 

 stretch far inward into the tissues of the body, are more in 

 consonance with a pelagic habit than are the bristles and feet 

 of the Sigalionidse. Further, the bristles themselves have a 

 closer approach to those of the Syllids than to any other 

 group, even to the serrations on the enlarged distal region of 

 the curved shafts. The simple condition of the dorsal bristle 

 is akin to that observed in St/llis spongicola and S. gracilis, 

 whilst even a more complex arrangement is seen in Ancistro- 

 stjllis greenlandica . On the other hand, the presence of teeth 



