222 THE ANNELIDA POLYCHAETA. 



All notocirri are attached toward the distal end of the parapodia. In a some- 

 what similar way the parapodia of the anterior region are divided into two groups 

 as to the character of their neurocirri, but these two groups do not correspond 

 to those based on differences in notocirri. The first four pairs of parapodia are 

 distinguished from the others in having the neurocirrus large, flattened, and 

 abruptly narrowed to an acute and asymmetrical tip. The neurocirri of suc- 

 ceeding parapodia of the nereid division are of ordinary form, and much more 

 slender, conically acuminate to a finely acute tip. All neurocirri are attached 

 well toward the base of the parapodium, as usual. The anterior parapodia 

 are of the usual biramous and biacicular type. Aside from the low acicular 

 process, the notopodium presents two ligulae which are short and bluntly 

 rounded, the notocirrus being attached at the base of the dorsal one of these. 

 The neuropodium presents a single ligula which is on the ventral side. It is 

 short and stout and bluntly rounded, thicker but not longer than the acicular 

 process. In the heteronereid division of the body the parapodia are longer 

 and are strongly compressed anteroposteriorly and the appendages present the 

 usual foUaceous developments. The notopodium has the two ligulae much 

 enlarged, thin and fohaceous; the dorsal one is slenderly sublanceolate in out- 

 line; the ventral one is much larger and extends proximad along the ventral 

 edge of the notopodium into a large auricle. The neuropodium bears distally 

 a very large, transparent, foUaceous appendage which is broadly ovate in out- 

 line and extends proximad along both dorsal and ventral side of neuropodium 

 into a rounded auricle, of which the ventral one is smaller and farther distad. 

 The ligula proper of the neuropodium is attached on the ventral edge proximad 

 of the end, extends first ventrad, and then distad at a right angle. The noto- 

 cirrus presents a style of ordinary form which is strongly varicose along the 

 ventral side and extends beyond the tip of the dorsal ligula; on the dorsal side 

 of its base is a thin, leaf-like expansion which is rounded distally but extends 

 proximad into an acute, auricular lobe. The neurocirrus is attached on the 

 ventral side at the very base. Arising in the middle is the slenderly tapered 

 style of ordinary form; on the distal side of the base arises a peculiar flattened 

 process which projects proximad of attachment into a short process with acutely 

 rounded tip and extends distad into a longer bifurcate appendage ; on the proxi- 

 mal side of the style is a large foUaceous appendage extending distad into a 

 distally rounded lobe and proximad into an acutely tipped lobe. In the para- 

 podia of the caudal region the same parts are present, but become much reduced 

 in size and the foUaceous appendages change more or less in shape and disappear 



