126 THE ANNELIDA POLYCHAETA. 



lad and caudad. Compressed, but little arched either dorsally or ventrally. 

 The length is 5.5 mm. The number of somites is twenty-nine. 



The prostomium is transversely oblong, with the anterior margin broadly 

 slightly convex and weakly notched at the middle. In the type all the tentacles 

 excepting one are lost, but the number seems clearly to have been four. The 

 tentacle is very short, slightly clavate, and is situated far out toward the antero- 

 lateral corner and in front of the eye. There are two pairs of eyes, one dorsal 

 and one ventral in position, all small, but the ventrals much larger than the 

 dorsals. The dorsal eyes are elliptic, with their axes longitudinal and inclined 

 to each other. They are wide apart. The ventral eyes are elliptic, or rather 

 somewhat obovate, and are similarly wide apart, each being at the anterolateral 

 corner. (Plate 19, fig. 1). 



The peristomium is of nearly the same length and width as the prostomium, 

 the two together being shorter than the second somite. The peristomium is 

 setigerous, but the setigerous papilla is very low and rounded. The setae are 

 few, and, so far as could be judged from the type, exclusively of the short, stout 

 type prevailing in the neuropodia of ordinary parapodia. There are two pairs 

 of tentacular cirri, of which the dorsals are lost. The ventral ones are small, 

 nearly of the same size as the tentacles and the ventral cirri of the ordinary 

 parapodia, though not so much tapered as the latter usually are. (Plate 19, 

 fig. 1). 



The first ones of the metastomial somites are less than twice as wide as 

 long. Those in the middle region are a little more, and those in the caudal 

 region are decidedly less than twice as wide as long. 



The pygidium is subcylindrical, with the caudal margin running to a very 

 obtuse angle at the middle. (Plate 19, fig. 2). 



The parapodia are biramous, a shallow notch at the distal end separating 

 a broad but low, rounded, or mesally somewhat angular lobe from a much 

 smaller, similarly short ventral lobe. The parapodium as a whole is about half 

 as long as the width of the somite; deeper dorsoventrally than anterocaudally; 

 narrowed distad both as viewed from above and from in front. The neurocirri 

 are small, cylindrical and slender and comparable in size to the tentacles and 

 ventral tentacular cirri, moderately tapered distad, 'each attached distad of 

 the middle of the neuropodium and a little surpassing the end of the latter. 

 The notocirri are cylindrical, distally tapering to a point; in the anterior region 

 long, clearly exceeding the dorsal setae, and when laid across the somite extending 

 beyond the tip of the opposite parapodium; becoming shorter caudad; each is 



