102 U.S. NATIONAL MUSEUM BULLETIN 227 



Genus Microphthalmus Mecznikow, 1865 



Type (monotypy): Microphthahnus sczelkowiiMeczmkow, 1865. 



Both species are of small size, vermiform, widest in the middle and 

 attenuated at both ends, convex dorsally, flattened ventrally, with 

 segments deeply incised. Prostomimn rounded anteriorly and later- 

 ally, nearly straight to slightly concave posteriorly, with a pair of 

 small posterolateral eyes (may be absent), with additional few scat- 

 tered pigment granules, with a pair of filiform lateral antennae dor- 

 sally, a shorter pair of filiform palps ventrally, a slender occipital 

 median antenna attached posteriorly (fig. 27a). Three distinct 

 achaetous tentacular segments each with 2 pairs tentacular cirri, an 

 upper and lower pair. 



The tentacular cirri arise from inflated cirrophores, the styles being 

 wide basally, tapering distally to slender tips. Tentacular cirri of 

 first segment and lower pair of second segment nearly equal; upper 

 pair of second segment about twice as long; upper pair of third segment 

 still longer, lower pair about a fourth as long. Parapodia unequally 

 biramous. Notopodia reduced to an aciculum and usually a single 

 notoseta in the bulbous inflated cirrophore of the dorsal cirrus. Dor- 

 sal cirri short, digitiform, not extending much beyond the neurosetae. 

 Neuropodia cylindrical, tapering to a bluntly conical lobe distally. 

 Neiu-osetae compound, with blades long to short. Ventral cirri short, 

 digitiform, extending about as far as the neuropodia. Eversible 

 proboscis surrounded by a circle of conical papillae distally, without 

 jaws (?). 



Key to the New England Species of Microphthalmus 



1. Anal or pygidial plate hood shaped, with border entire (fig. 27c). Body 

 dotted with brown pigment in poorly defined transverse bands, and 



especially dark laterally M. sczelkowii 



Anal plate a flat bilobed structure (fig. 276). Body white or only slightly 

 dusky M. aberrans 



Microphthalmus sczelkowii Mecznikow, 1865 



Figure 27c 



Podarke caeca Webster and Benedict, 1884, p. 706, pi. 1, figs. 6-8. — Miner, 1950, 



p. 300, pi. 99. 

 Microphthahnus sczelkowii Southern, 1914, pi. 45, pi. 5, fig. 6,a-e. — Fauvel, 



1923, p. 250, fig. 93,a-/.— Uschakov, 1955, p. 197, fig. 59.— Rasmussen, 



1956, p. 49, figs. 14-16. 



Description. — Length up to 6 mm., width including setae up to 

 0.5 mm., segments up to 40. Notoseta simple, curved, lyrate. 

 Color: body richly supplied with brown pigment scattered on the 

 prostomium and anal plate, laterally ne^tr the bases of the parapodia 



