1910.] NATURAL SCIENCES OF PHILADELPHIA. 371 



— is known. It is attached to II and covers most of the prostomium 

 and immediately adjacent region. It is irregularly orbicular with 

 a very small subcircular scar of attachment, remarkably thick, soft 

 and of cushiony texture, the outer surface and borders everywhere 

 thickly covered with peculiar large, soft hemispherical or dome-shaped 

 soft papilla?, each bearing at its summit a single coarse filament or 

 cilium. Postero-laterally these become larger and frequently con- 

 fluent in twos and threes to form bilobed of trilobed papillae. 



The specimen is entirely unpigmented ; the cuticle is thin and the 

 tissues delicate and translucent with large nerves visible through it. 

 In many places the tissues are more or less inflated. These appear- 

 ances call to mind the conditions of the similarly abyssal Laetmonice. 



This species is closely related to the imperfectly known Polynoe 

 (Adametella) longipedata Mcintosh from the North Atlantic, but the 

 latter has stout notopodial setae peculiarly bifid at the tips. 



Station 4,397, off Santa Catalina Islands, lat. 33° 43' N., long. 117° 

 42' W., 2,196-2,228 fathoms, gray mud (type only). 



APHRODITID^E. 



The type genus abounds in this region, being represented in the 

 collection by five species, two of which are evidently abundant. They 

 vary in size from the little aberrant A. parva, sometimes less than 

 ten millemeters in length to huge bulky specimens of A. japonica 

 seven inches in length and nearly three inches wide. Three of the 

 species have not been described previously. Less common is Laetmo- 

 nice, represented by two species, one of which (L. producta ivyvillei) 

 occurs at the greatest depth (2,228 fathoms) at which Polychaeta were 

 taken by this expedition. 



Aphrodita armifera sp. nov. PI. XXXI, figs. 65, 66; PL XXXII, figs. 67-75. 



This very noteworthy species is represented by a single specimen. 

 From broad ovate, the anterior end broadly rounded, the greatest 

 width at XV, which is the middle of the length, the width rapidly 

 reduced after XXI, and segments after XXVII forming a slender 

 attenuated caudal region. Moderately depressed, the dorsum less 

 arched than in many species and covered with a thin, clean layer of 

 felt fibers at the sides of which the great lustrous brown spines are 

 quite uncovered and rise over the back much as in a Hermione, the 

 largest ones meeting or nearly meeting in the middle line. 



Prostomium (PI. XXXII, fig. 67), deep sunken between the parapodia 

 of I and II and completely concealed by the elytra and felt, regularly 

 ellipsoidal, the width about one and one-third times the length; 



