1909.] NATURAL SCIENCES OF PHILADELPHIA. 335 



One is a female filled with large eggs distinctly visible to the naked 

 eye; the others, including the type, appear to be males. 



Sphaerodorum brevicapitis sp. nov. PI. XV, figs. 13, 14. 



Although considerably larger this species closely resembles S. 

 papillifer in general appearance. The type and only specimen, much 

 contracted and distorted, is 39 mm. long, with a maximum diameter 

 without parapodia of 1.6 mm., and has 96 segments. 



Owing to the partial protrusion of the proboscis as a soft bulbous 

 structure the prostornium is crowded dorsad. It appears as a very 

 slight, scarcely distinguishable lobe, bearing scattered papilla?, of 

 which five, though still small, are larger than the others ; three of these 

 are very close together near the anterior margin of the lip ; the others 

 are separated by a considerable interval on each side. 



Peristomium likewise indistinct — a short achaetous ring bearing a 

 minute mammilliform papilla on each side. A pair of rather large, 

 widely separated pigment spots, the remains of a pair of eyes, lies 

 partly on this segment but chiefly on III. Owing to the condition of 

 the specimen little can be determined about the normal appearance of 

 the segments. The cutaneous papilla?, however, are less numerous 

 and smaller than in S. papillifer. They are scattered fairly uniformly 

 over the surface, becoming more numerous on the parapodia. Pygi- 

 dium a minute ring bearing a pair of low, broad, mammilliform papilla?, 

 besides at least two small, simple papilla?. 



Parapodia (PI. XV, fig. 13) in general similar to those of S. papillifer, 

 but the parts more widely separated and the neuropodia more slender 

 and cylindrical with a conical apex, rather than simply conical, and 

 ending in a small postacicular lobe. Neurocirri small, subcorneal 

 processes arising from the posterior ventral side of the neuropodia just 

 at the base of the terminal cone. Spherical organ prominent, with a 

 thinner cuticle than in S. papillifer, and the papilla borne on the ventral 

 side of the base instead of on the outer surface. Dorsal papilla (noto- 

 cirrus) well above spherical organ, small, claviform, with a widened 



base. 



Aciculum single, rather more slender than that of S. papillifer, 

 but similar in form, colorless, the blunt-pointed tip projecting freely. 

 Seta? in irregular fascicles of usually eight or nine, rather prominent, 

 all compound or semi-compound, becoming widened and flattened 

 distally and then tapering into a hooked tip or appendage which is 

 articulated to the stem by an oblique joint, the absence of which would 

 leave these seta? very similar to those of S. papillifer (PI. XV, fig. 14). 



