308 THE ANNELIDA POLYCHAETA. 



distad abruptly beyond the notocirrus to the subcircularly rounded, flattened, 

 presetal hp; the postsetal process rounded at the end and attached farther 

 proximad, and almost reaching distad to the tip of the postsetal lip ; the ventral 

 cirrus is attached at base of parapodium; it is a tapering piece of nearly same 

 form and size as the postsetal process or median cirrus ; notocirrus more slender 

 than median cirrus, tapering, not reaching to end of postsetal lip. (Plate 39, 

 fig. 4). The second parapodia are in general similar to the first ones, but are 

 shorter and are directed more ectad; the terminal button or postsetal lip is 

 smaller; the neurocirrus is decidedly more swollen proximally; the notocirrus 

 is longer and, conspicuously beyond the postsetal lip, or tip. (Plate 39, fig. 5). 

 The third parapodia are abruptly much shorter than the preceding; the presetal 

 lobe is further reduced and is less rounded, distally pointed; the postsetal process, 

 or median cirrus, much exceeds the end of the parapodium; the ventral cirrus 

 is a much thicker, subconical, distally rounded process; the notocirrus much 

 exceeds the tip of the presetal process, but is shorter absolutely, though not 

 relatively, than that of the preceding pair. The fourth pair are much shorter 

 than the third and extend almost directly ectad, their direction making a con- 

 spicuous angle with that of the preceding ones; the presetal lobe is further 

 reduced and relatively narrower; the neurocirrus appears as a conspicuous 

 subglobular tubercle, a character maintained on the following parapodia. The 

 succeeding parapodia become gradually shorter and finally appear simply as 

 rounded eminences on which the presetal and postsetal processes have become 

 reduced to mere points, or quite obliterated. Caudad from the fourth para- 

 podia the length of the notocirri for a while remains nearly constant; they then 

 undergo a marked reduction in size and finally disappear at or near the thirty 

 second somite. 



Setae of first parapodia few, long, stout ; compound, the oblique articulation 

 distinct; setae conspicuously curving near level of and especially above the 

 articulation; terminal tooth short, conspicuously curved; the accessory tooth 

 short, straight, widely separated from the apical one; guards well developed, 

 distally rounded, somewhat obliquely prolonged. (Plate 39, fig. 8). Acicula 

 of first parapodia slenderly acutely pointed, the tips not much protruding. On 

 the second parapodia there appears a conspicuous fascicle of usually numerous, 

 fine, transparent pectinate setae in a dorsal group, each with the usual slender 

 stalk and clavately expanded, curved end piece with the series of teeth along 

 distal border; these pectinate setae occur also on the succeeding parapodia, 

 as usual. (Plate 40, fig. 1). On the second parapodia also appear simple setae 



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