460 THE ANNELIDA POLYCHAETA. 



caudad, but widens slightly at the very end. The dorsum is strongly convex, 

 the venter flattened. The total length of the type is 43 mm., of which the 

 abdomen composes about 24 mm. The greatest width of the thorax is 4 mm. ; 

 the width of the abdomen at its base, 2 mm., and at its narrowest point, which 

 is about 2 mm. from the end, 1 + mm. The total number of somites is forty. 



The body is somewhat brownish yellow throughout. The glandular 

 ventral ridge between each two parapodia of the same pair is whitish. 



Prostomium with anterior region strongly depressed, leaving an elevated 

 transverse region behind, from the median part of which extends cephalad a 

 lobe presenting two short, cylindrical, distally rounded processes, which are 

 separated by about half their diameter and which project directly forwards 

 and are essentially parallel. (Plate 76, fig. 7). 



The peristomium forms ventrally a conspicuous lower lip, of which the 

 anterior and lateral margins form a subsemicircular outline, or the anterior 

 margin may be mesally more or less indented ; lying in a dark, transverse band 

 is a transverse sulcus from which two short, submedian sulci extend forwards 

 to the anterior edge. The anterior border is paler. (Plate 76, fig. 7). The tenta- 

 cles are moderate, cylindrical, and somewhat expanded at the tips. 



The branchiae are more or less flattened, narrowed over the distal portion 

 to a slender, apical portion, and commonly present a subulate tip. They are less 

 than twice the width of the body. (Plate 76, fig. 8). 



Segments II to IV are prominent ventrally, flaring below the general level 

 of the thorax. Of these the first is ventrally longer than the second, and the 

 second than the third, which is of same length as the fourth. Dorsally somite II 

 is also longer and presents each side of the middle a short, angular process, or 

 tubercle. From the fourth somite caudad the somites increase conspicuously 

 in length. The length of the seventeenth somite on the ventral side in the type 

 is 2.2 mm. The abdominal somites decrease in diameter regularly caudad. 

 The pygidium flares a little about the anus in a weak trumpet-form, the inner 

 surface being radially ridged. 



The first notopodium on each side is a low, rounded tubercle from which 

 the setae project almost directly cephalad. From the second one the notopodia 

 increase in length to the middle thoracic region, where they are long and sub- 

 cylindrical, in the type being here about 1.3 mm. in length. Beneath the distal 

 end of each one a cirrus is represented by a small, conical tubercle. (Plate 77, 

 fig. 9). The setae of the first segment are fewer and much shorter, those of the 

 second intermediate. 



