374 Dr. Johnston on the British Annelides. 



the description more distinct, it may be advisable to consider 

 it as divided into an anterior and a caudal half. 



The anterior half consists of about 14 segments, increasing 

 gradually in diameter till near the middle, when they begin 

 again to decrease a little. The first or cephalic segment is 

 very small, pellucid, triangular, sharp-pointed like a snout, 

 and somewhat concave underneath : it is destitute of every 

 kind of appendage. The second segment is rather broad, and 

 like the succeeding, excepting that it is single and without any 

 armature. The other segments consist each of two, or some- 

 times three narrow rings ; and each of them is furnished, on 

 each side, with a dorsal brush of bristles, a long filament, a 

 circular pore, and a ventral brush of bristles, similar to the 

 dorsal, but smaller. On the secondary or intermediate rings 

 there are no bristles, but one, two, or even three pores. The 

 mouth is perforated between the third and fourth segments on 

 the ventral surface ; it is circular, with thickened puckered 

 lips, edentulous, and without a proboscis. 



The anterior segments pass by a sort of gradation into the 

 caudal ones, though it is not difficult to mark the distinction. 

 They are less in diameter, but broader in the opposite direc- 

 tion, and thickened on the sides, where there are two short 

 obtuse fleshy papillae. From the base, and below the dorsal 

 papilla, the soft filament or cirrus originates, which does not 

 exceed half the length of the anterior filaments. Close to the 

 cirrus there is a brush of bristles, but I could not discover a 

 second brush. There are thirteen of these caudal segments 

 with a very narrow one between each : the last but one is 

 small and unarmed, and the anal one is terminated with six 

 soft obtuse papillae forming a sort of cupped circle round the 

 vent. 



The skin of the worm, under a magnifier, appears to be 

 granulated on the dorsal, and punctured on the ventral sur- 

 face. The bristles are slender, unequal, shghtly curved, aci- 

 cular, smooth, and unjointed : they vary in number in the seg- 

 ments, but scarcely exceed twenty in any single fascicle, and 

 are never fewer than four or five. Those of the dorsal brush 

 are longer than those of the ventral, but do not otherwise differ; 

 and both brushes come from the skin, and not from a papil- 



