390 PROCEEDINGS OF THE ACADEMY OF [April, 



downward to nearly or quite touch the notopodium. Ctenidia (fig. 

 100c) form three long nearly continuous ciliated cushions, the ventral 

 occupying about the proximal two-thirds of the dorsum of the foot, 

 the intermediate nearly as long a space at the bottom of the bay, and 

 the dorsal a slightly shorter distance reaching nearly to the base of the 

 branchia. 



Elytrophores occur on II, IV, V and alternate somites to XXVII 

 and then on every somite. The first three are small, low and cylin- 

 droid and situated on the base of the parapodia; following ones soon 

 become more elevated, separated from the parapodia and provided 

 with ovoid scars and protruding lateral ends. At XXVII and beyond 

 they become still more prominent and tumid. Branchiae (notocirri) 

 occur on elytrophorous segments only and first appear as a minute 

 non-ciliated process on the overhanging end of the elytrophore at 

 XIII. They undergo little change to XXVII where they rather 

 abruptly become larger and ciliated and continue to increase in size 

 as above indicated. 



Elytra are easily detached and most of them lie loose in the bottle. 

 The first two are small and nearly circular with central attachment. 

 Those following (probably as far as XXV) are more or less rhomboid 

 or trapezoid (PI. XXXIII, fig. 101a) with rounded corners and slightly 

 concave or indented sides and the scar somewhat laterad of the center; 

 the others are irregularly narrowly ovate with the broad end laterad 

 and scar nearly central, a well-marked umbilicus and deep lateral 

 emargination, resulting in a somewhat trilobate outline (fig. 1016). 

 Apparently the dorsum is incompletely covered in the anterior region 

 but completely covered after XXVII, though the elytra cannot overlap 

 much medially. All elytra are soft, flexible, perfectly colorless, 

 smooth and free from cilia or definite papillae. Some of them (fig. 

 1016) exhibit one to three large, bleb-like elevations along the lateral 

 margins which may be, however, pathological. Internally they are 

 composed of a mass of vertical fibers among which the nerve fibers 

 and nerve cells and slender end organs may be seen. 



Acicula yellow; setse all colorless. Notopodial setae in a spreading 

 whorl arising along a long curved line which becomes more restricted 

 to the dorsum anteriorly. All are slender and capillary, some quite 

 smooth, others hispid with small stiff hairs arranged in oblique rings 

 or part rings toward the base of the setae (PI. XXXIII, fig. 104a) this 

 arrangement being gradually replaced in the middle region by one of 

 larger nearly opposite paired spines (fig. 1046) which gradually become 

 reduced and disappear, leaving a long and very delicate smooth tip. Such 



