1910.] NATURAL SCIENCES OF PHILADELPHIA. 389 



quadrant round the aciculum as a center. Frequently a fourth short 

 series is detached from the dorsal end of the antero-ventral series and 

 passes obliquely in part between the latter and the postero-interme- 

 diate series. Notopodium about half as deep as the neuropodium and 

 partly overlapping it behind, slightly compressed and with gently 

 curved outlines, the distal end divided into two short blunt lobes, the 

 ventralmost of which receives the tip of the curved aciculum while 

 from the furrow between arises the long rank of setse along a curved, 

 sickle-shaped line with stout anterior and much longer posterior limb 

 passing down the posterior face of the notopodium. Round the outer 

 face of the seta? is a series of seven or eight stylodes more slender than 

 those on the neuropodium, in addition to two or three more dorsal 

 detached ones and a very much larger one with constricted base and 

 widened middle attached immediately above the tip of the aciculum. 

 Dorsal to the parapodium is a deep and wide bay bounded dorsally 

 by the elevated and projecting elytrophore, from the overhanging 

 tip of which projects a minute blunt notocirrus (branchia). On this 

 and more anterior segments ctenidia are absent and the epidermis 

 of the supraparapodial bay is quite smooth. Neurocirrus arising 

 from a low cirrophore near base of neuropodium; style reaching 

 nearly to base of ventralmost setse, rather stout at base, tapered regu- 

 larly to an obscurely articulated end bearing a small rounded tubercle 

 on the dorsal side of the base. Other parapodia in the region differ 

 somewhat in the number and form of the stylodes which appear to be 

 somewhat caducous and contractile. 



Toward the cephalic end the entire foot becomes shorter, the noto- 

 cirrus disappears, the neurocirrus becomes short and stout and the 

 end of the notopodium turns round the tip of its aciculum and faces 

 dorsad, presenting a very characteristic rosette of stylodes from the 

 center of which springs a small whorl of capillary seta?. Beginning 

 at IV the parapodia bend successively more forward, that of II pressing 

 the peristomial parapodia closely and reaching to its end (PL XXXIII, 

 fig. 100a). Caudally of XXV the parapodia soon become relatively longer 

 and their stylodes more slender or extended ; near the end of the piece 

 the neurocirri are again shorter but continue slender. At about XXX 

 (XXIX in this specimen) slender stylodes appear in front of the antero- 

 dorsal setae of the neuropodium and three or four continue to be present 

 in this position to the end of the piece. At XXVII well-developed 

 ciliated pads or ctenidia appear in the dorsal bay and the notocirri 

 (branchia?) begin to become much larger, swollen, and ciliated. When 

 fully developed as on somite L (fig. 100c) they are very stout and hang 



