1910.] NATURAL SCIENCES OF PHILADELPHIA. 377 



the very short basal segment more than one-half the width of prosto- 

 mium, the rest regularly tapered, only moderately slender, about seven 

 times as long as the prostomium, with slender pointed tips and bearing 

 minute sensory cilia. Facial caruncle a rather prominent, nearly 

 smooth plate, very thin and strongly compressed between the bases 

 of the palpi but somewhat swollen above, terminating above mouth 

 in a short blunt papilla. In all the specimens this papilla is much 

 shorter than on most species. 



Peristomium a short transverse dorsal fold united to the prostomium 

 by the nuchal isthmus and forming the anterior lips ventrally. Peristo- 

 mial parapodia (PI. XXXII, fig. 78) much prolonged forward, reaching 

 beyond the prostomium fully twice its length, much compressed to near 

 the end which is expanded but not divided into rami; distal end re- 

 ceiving a dorsal aciculum only and bearing three dense flat tufts of 

 capillary seta?, one above the notocirrus, one above and distal to the 

 neurocirrus and the third ventral and much more proximal. Tentacular 

 cirri borne on distal end of medial face of peristomial parapodia. 

 Both consist of short ceratophores and slender tapered styles about 

 one-fifth as long as the palps and with scarcely developed terminal 

 bulb. Mouth bounded by peristomium and posteriorly by a long 

 quadrate lip that occupies the entire middle region of somites II and 

 III and cuts into IV. Anus a small dorsal slit with furrowed rim 

 cutting through the last 4 segments. 



Metastomial segments flat below, the boundary between segments 

 and parapodia clearly defined by a deep continuous trench. Segments 

 indicated by thick and deep transverse integumental folds; neural 

 area not sharply differentiated from muscular area. Cuticle thick 

 and opake on the venter, studded with spherical papillae, much smaller 

 and less crowded than on A. castanea, dorsally thinner and on the 

 body smooth with few and scattered minute conical, capped papillae 

 (Pi. XXXII, fig. 76) which become much more numerous on the bases 

 of the parapodia. 



Elytra fifteen pairs, borne on II, IV, V and alternate segments to 

 XXIII and then somewhat doubtfully on XXV, XXVIII and XXXI, 

 following which are eleven small segments tapering to the minute 

 pygidium. Elytra all large, widely imbricated and completely cover- 

 ing dorsum of body and head; they are thin, flexible and tough, 

 having the same form and mode of attachment as in A. castanea. 

 The last pair folded into a tube enclosing the caudal segments. Dorsal 

 fimbriated organs begin on VI and alternate with the elytra to XXX, 

 the last two pairs being rudimentary. The others are erect, compressed 



