142 THE ANNELIDA POLYCHAETA. 



length. In the wide middle region they are about three and a third times wider 

 than long. The somites are but weakly convex and are nearly equally so dor- 

 sally and ventrally. Ventrally there is a weak neural furrow, and the somites 

 are entire, or at most show but a vague transverse furrow on each side mesad of 

 parapodia. The anterior margin of the first somite ventrally, which borders 

 the mouth, is straight, and the border immediately caudad of the mouth slopes 

 caudoventrad to the general level. (Plate 23, fig. 2). 



There is a ventral glandular papilla at the base of each parapodium of 

 somites XII to XVI in the paratype. These are long, cylindroconical, and 

 conspicuous. In the type they are thicker and lower. 



There are five pairs of tentacular cirri, or rather six, counting the ventral 

 cirri of the fourth somite, of which one pair is borne on the first somite and 

 two pairs each on the second and third somite. The cirri of the first somite 

 are the neurocirri; they are conical and of moderate length, extending outward 

 a little beyond the base of the ocular lens. The ventral tentacular cirri of the 

 second somite are similar in form and size to those of the first, while the ventral 

 ones of the third somite are smaller, though maintaining the conical form. The 

 dorsal tentacular cirri of the second and third somites are much larger than 

 the others and are subequal in length; they extend ectad distinctly beyond 

 the outer edge of the eyes, are gradually tapered from the base to an acute tip, 

 and are a little flattened. (Plate 23, fig. 1, 2). 



On the fourth somite the dorsal cirri of the parapodia are short, ovate, and 

 strictly foliaceous; the neurocirri are subcorneal, scarcely flattened, of nearly 

 same form and size as the ventral tentacular cirri of the third somite, as a sixth 

 pair of which they might be regarded. No setae could be detected on this 

 somite. The parapodia of the fifth somite are setigerous; the setigerous lobe 

 or neuropodium is distally rounded, showing no trace of a process, and bearing 

 a series of four or five stout setae of the crochet-type with but two or three of 

 the five capillary setae on the dorsal side; the neurocirrus is foliaceous and 

 broadly attached to the neuropodium, its distal end scarcely free and not attain- 

 ing end of neuropodium; the notocirrus exceeds the neuropodium. In succeed- 

 ing parapodia the number of crochets increases to about seven and gradually 

 toward the caudal region the capillary setae increase in number, and posteriorly 

 are very numerous. In general the notocirri are large and overlap; in the anter- 

 ior region they are broad, somewhat "ovate-reniform, and auriculate at base. 

 Farther caudad they appear relatively broader,^but are always angulate at the 

 distal end. Caudad the neurocirri become much larger and extend beyond the 



