278 PROCEEDINGS OF THE ACADEMY OF [April, 



maximum diameter is probably not quite attained in these pieces. 

 The first few segments are firm-walled and bounded by deep furrows, 

 but farther back they become softer and the furrows shallower. All 

 are nearly terete, but slightly flattened and grooved ventrally. Py- 

 gidium a very small, short, truncate cone bearing a pair of very slender 

 tapering cirri about one and one-fourth times the greatest diameter 

 of the body. 



Parapodia generally similar to those of larger species, but relatively 

 less enlarged and prominent. First pair (on II) largest, projecting 

 forward and slightly ventrad, but barely reaching level of anterior 

 border of palps, truncate, conical, transversely furrowed and terminated 

 by a broad, flat, prominent, preacicular lip and a slender but about 

 equally long, more cirriform postacicular lip. Both notocirri and 

 neurocirri are simple, conical styles without differentiated cirrophore 

 and of similar form and size, not quite reaching the end of the terminal 

 lips, the neurocirrus arising on the antero-ventral part of the base of 

 the neuropodium close to the side of the mouth, the notocirrus nearly 

 half-way out on the postero-dorsal aspect of the foot. The second 

 foot (PI. XVIII, fig. 86) is similar, but decidedly smaller and projects 

 very little forward and ventrad. The third is modified still farther 

 in these respects, and the fourth (fig. 87) has attained the typical 

 position and nearly typical proportions and differs particularly from 

 preceding parapodia in its much shorter, blunt neurocirrus. The one 

 figured (fig. 87) has the postsetal lip abnormally bifid. On the first 

 parapodium the postsetal lip is shorter than the presetal, but on the 

 second this relation is reversed and the latter disparity becomes more 

 pronounced on succeeding parapodia until at somite X the postsetal 

 lip becomes again reduced to the length of the presetal lip and assumes 

 the form of a small cylindroid papilla. This continues to diminish, 

 shifts to a more ventral position and finally disappears, leaving only 

 the short, broadly rounded presetal lip of the low, flat parapodia of 

 middle segments (fig. 88). Notocirri undergo very regular and gradual 

 diminution in size and with the appearance of the gills (about XX) 

 have become quite minute and little longer than the presetal lip, ap- 

 pearing as small processes from the outer side of the base of the gills. 

 Neurocirri remain the same for the first three parapodia and then very 

 abruptly become altered to a small, thick papilla, which in the course 

 of one or two more segments becomes absorbed into a low swelling 

 and extensive glandular region ventral to the parapodium. 



On the cotype gills begin symmetrically on XIX ; on the type there 

 is a small one on one side of XVIII, fully developed ones on both sides 



