no THE ANNELIDA POLYCHAETA. 



prevailing in the remaining portion of the anterior region generally. (Plate 16, 

 fig. 9). A typical parapodium, as for example the seventieth, has a notocirrus 

 consisting of a short thick cirrophore and an elongate ovatolanceolate fohaceous 

 style. The neuropodium is compressed in the cephalocaudal direction, its 

 distal end very obtusely angular, with an entire presetal lip and a mesally 

 notched postsetal Up which is higher than the presetal one. The neurocirrus 

 is small, more narrowly lanceolate than the notocirrus, and extends distad a 

 little beyond the apex of the neuropodium. (Plate 16, fig. 11). Caudad the 

 parapodia retain the same general structure but become much smaller. The 

 style of the notocirrus becomes more regular and proportionately broader, 

 more ovate, but with the apex strictly angular. The neurocirrus retains the 

 same form as farther forward, but it is proportionately to the notocirrus broader 

 and longer in a marked degree. In the third setigerous parapodium the style 

 of the notocirrus is more oblong, as wide at the beginning of the distal third as 

 across the base, but with the upper edge incised between these two regions and 

 the apex angularly pointed though not much elongate; the neurocirrus, much 

 exceeding the neuropodium in size, is normally elliptic and weakly sigmoid, 

 the distal end rounded, not at all angular, the lower end free, more narrowly 

 rounded, auriculiform. The second setigerous parapodium is similar to the 

 third excepting for the conspicuously smaller size of the notopodium. 



The setae are all colorless and transparent, and comparatively few in number. 

 They are arranged, as usual, in single series in which they spread out somewhat 

 in a fan-like manner. They are shorter than the neuropodia. On the seventi- 

 eth somite the setae are fourteen to sixteen in each parapodium, while one from 

 the narrower posterior region has only about eight. 



The shaft of a seta as a whole is slightly curved, the convexity dorsad; 

 at its distal end it is enlarged and spinous in the usual way. The blade is longer 

 than the free portion of the shaft. It narrows distad to a very fine tip and as a 

 whole is curved, the convexity dorsad, and the convex dorsal edge finely, closely 

 serrate. 



The fully extended proboscis of the type is 6 mm. long and 1.8 mm. thick. 

 At the apex there is a ring of eighteen papillae of good size, these close together, 

 flattened in the direction of the circumference of the ring which they form, and 

 distally rounded. The papillose basal division is but a sixth, or slightly more, 

 the total length of the proboscis. On it the papillae, which are short, distally 

 rounded, and flattened in the direction of the long axis of the proboscis, are 

 densely arranged with no trace of series. The long distal division of the pro- 



