388 THE ANNELIDA POLYCHAETA. 



The succeeding somite, i.e., the second, is also biannular. Each annulus 

 with a single transverse row of low, rounded papillae along the caudal border, 

 with cephalad of this smaller papillae hke those of the preceding somite, with 

 the integument between the annuli proper appearing somewhat tesselated. 

 The second annulus of the second somite is incomplete laterally and the first 

 is deeply grooved ventrally where it borders the mouth on its caudal side. On 

 each side of this somite between the two fascicles of setae is a sensory pit, the 

 mouth of which is vertically lenticular in form. The third somite is triannulate, 

 with the third annulus indistinct laterally. Papillae and integument as in the 

 preceding somite. The following somites to and including the fourteenth are 

 similarly triannulate in form, with papillae and integument the same. The 

 fifteenth segment is incompletely triannulate, the two more caudal annuli being 

 indistinguishable from each other laterally. The sixteenth and seventeenth 

 somites are biannular, and the remaining somites are entire, or uniannular, with 

 the annuh distinctly and abruptly larger than those of the preceding somites and 

 with correspondingly more numerous, large, vesicular papillae, the papillae 

 decreasing in size from the caudal edge cephalad to the interannular tesselated 

 integument. The papillae are absent along the sides from a level a little above 

 the upper setae to one a little below the lower ones, giving the effect of a longi- 

 tudinal furrow along each side of the body, with the papillae above and below 

 the groove large. (Plate 67, fig. 1). 



The branchiae first appear on the third somite and occur on each one there- 

 after to and including the fourteenth, but are quite absent from all others. 

 Each branchia is subfiliform, proximally subcyhndrical, gradually narrowing 

 distad, conically acuminate at tip; strongly transversely wrinkled. (Plate 67, 

 fig. 1, 3). Those of the sixth to twelfth (Plate 67, fig. 4) somites longest, those 

 of the fourteenth very short, with the thirteenth intermediate and the most 

 anterior ones also very small. The longest ones in the preserved specimens do 

 not exceed the length of the somite. Each branchia is inserted above the 

 lateral sensory pit close to the notopodial setae on the third, or on the fused 

 second and third, annulus of the somite. 



The setae occur on somites from the second inclusive caudad. They arise 

 from pits with slit-like openings into which they are apparently more or less 

 retractile. (Plate 67, fig. 3, 4). They are pale, very fine, capillary forms of 

 varying length, those of the notopodial tufts longer than the ventrals, as usual. 

 Pygidium short, conicocylindrical, truncate distad, divided by longitudinal 

 sulci into ten or eleven lobes in the usual manner. (Plate 67, fig. 1). 



