POLYNOIDAE 43 



The dorsal cirri reach to the tips of the bristles and the ventral are shorter than the 

 feet. The parapodia (Fig. 7, b) are biramous, the dorsal branch consisting of a small 

 lobe containing a sheathed aciculum\ but no bristles. The neuropodium has two rather 

 prominent, bluntly conical lips of about the same length, between which the bristles are 

 arranged in a vertical series. 



The upper and middle bristles (Fig. 7, c) are long, fine-scaled capillaries ending in a 

 delicate, whip-like tip. Below these are about a dozen much shorter bristles (Fig. 7, d), 

 expanded towards the apex, toothed above the expansion and ending in a bidentate tip. 

 The cylindrical clavate process, which adjoins the ventral cirrus, appears to be absent 

 from the first four or five feet. It is an enlarged genito-nephridial papilla. 



Remarks. This pelagic species is close to the Podarmus ploa of Chamberlin from 

 Easter Island, but is distinguished by the bidentate character of its lower ventral 

 bristles. 



Genus Sheila, gen. nov. 



Diagnosis. The lateral tentacles are inserted terminally as in Lepidonotiis. There 

 are 13 pairs of elytra inserted on segments 2, 4, 5, 7, 9, etc. The feet are biramous, but 

 the dorsal ramus is reduced. The notopodial chaetae are delicate toothed capillaries, 

 slightly finer than the neuropodials. These consist of long toothed capillaries, a few 

 shorter and stouter toothed bristles ending in a blunt hook, and in the middle of the 

 neuropodium a single giant bidentate hook. The genotype is bathypelagic. 



Sheila bathypelagica, n.sp. 



St. 256. 23. vi. 27. 35° 14' 00" S, 6" 49' 00" E. 850-1100 m. Gear TYF. One specimen. 



Description. The specimen measures 9 mm. by 2 mm. without the feet: there are 

 about 29 chaetigers and 13 pairs of elytrophores. In spirit the back is pale grey with 

 rather faint transverse segmental bands of a darker colour interrupted in the middle 

 line. The undersurface and the feet are a deep black; the tentacles and cirri are also 

 black except at their tips, but the palps are a pale grey. 



The head (Fig. 8, a) is longer than broad and bulged at the sides. The whole of the 

 lateral surfaces are occupied by two pairs of large contiguous eyes with white centres 

 and dark brown edges. The three tentacles leave the head at the same level, are all of 

 the same length, about two-thirds that of the prostomium, and end in a flagelliform tip. 

 Below the lateral tentacles is a pair of palps, each ending in a small mamilla ; they are of 

 about the same length as the tentacles but twice as thick. Set close to the side of the 

 palps is a pair of tentacular cirri about twice the length of the other appendages. Palps, 

 tentacles and cirri are smooth. All the elytra are lost. 



The dorsal cirri are long, reaching almost to the tips of the bristles, and the ventral 

 cirri are very short. 



^ There is no etymological warrant for the form aciciihim with phiral in a: the Latin acicula is a 

 feminine noun with plural in ac. The incorrect variant is, however, so firmly established as part of the 

 English terminology of the Polychaeta that I prefer to retain it. 



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