Gatty Marine Laboratory , St. Andrews. 165 



segment and at its rear being nearer each other, and the 

 posterior pair in front of the tori. The following, or 8th, 

 bristled segment inaugurates a change, for it has no dorsal 

 glandular bands, and posteriorly it is separated from the next 

 segment by a deep furrow — in frout of which are the tori, 

 the edges of which are dorsal, and the bristles, which like 

 those in front are near each other. Moreover, a couple of 

 dimples occur anteriorly on each side of the middle line. 

 Further, if it be held that the anterior segments have their 

 tori and bristles in front, then this segment (8th) has a 

 double series, those in rear being in front of the segment- 

 junction, and the bristles slant upward and forward. The 

 following segments bear the dorsal bristles on the outer edge 

 and widely apart from each other, and the tori are ventral in 

 position. The direction of the bristle-tufts after the 11th 

 abdominal segment is usually in the preparations more or 

 less transverse. Moreover, these posterior bristles, even to 

 the tip of the tail, are lateral in position. 



The segments gradually diminish in anteroposterior 

 diameter towards the tail, which is terminated by a com- 

 paratively large anus with a papillose margin, a few of the 

 minute segments adjoining it apparently having no bristles. 



The bristles throughout have the same structure and are 

 slightly pinnate at the extremity (Watson), those in the 

 posterior segments being fewer in number and proportionally 

 large and more slender. The tori form characteristic bands of 

 a multitude of minute crotchets, forming a dense series, each 

 ■with two well-marked terminal hooks, the posterior curve of 

 which is prominent at the tip, the neck, which is narrowed, 

 having a forward bulge anteriorly below the hooks, and with 

 a shoulder as it joins the shaft, which is long and slightly 

 tapered posteriorly to a delicate thread *. The hooks of the 

 specimens from St. Andrews are somewhat larger than those 

 of the more bulky Annelids from Naples, but are precisely of 

 the same structure, and thus differ from the somewhat abrupt 

 posterior end at its junction with the ligament as shown bv 

 Arnold Watson, the figure having probably been foreshortened 

 to suit the plate. All have a long shaft gradually tapering 

 towards the base and a distinct shoulder grasped by the 

 epiderm. The absence of a shoulder in the figure of Sars 

 may have been due to the imperfection of his microscope. 

 The tori of the first four segments are red from their 



* De St. Joseph calculates that there are about 7600 hooks per torus, 

 and perhaps about 450,000 in all. 



Johnson, in Puget Sound Annel., describes an Ammochares with bifid 

 uncini. 



