172 PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



length, the superior one somewhat gibbons and bearing the long, slen- 

 der, dorsal cii-rus beyond its middle; beyond the origin of the latter the 

 lingula is lanceolate, subacute at the end ; three conspicuous dark spots 

 on the superior lingula, one terminal, one at the origin of the cirrus, the 

 other midway between that and the body ; another spot on the body, at 

 base of the appendage. The inferior lingula is also lanceolate, a little 

 shorter than the superior. More than half the length of the dorsal cir- 

 rus projects beyond the end of the lingula. The ventral lingula of the 

 lower ramus is oblong-lanceolate, obtuse, considerably smaller than 

 the dorsal one. Ventral cirrus small, slender, acute, not reaching to 

 the end of the ventral lingula. SetsB in both the upper and lower rami 

 of two kinds: in the superior fascicle of each they have slender, 

 acute, terminal pieces ; in the inferior fascicle the terminal piece is short 

 and hooked at the tip. It is very active in all its motions, and swims 

 rapidly. It constructs a tenacious tube, attached to algre, and sup- 

 ported by divergent silken threads. Length, 2 to 3 inches. 

 Vineyard Sound, 8-10 fathoms, 1875. Described from life. 



Nereis megalops Verrill. 



Xcctonereis megalops Verrill, Eeport on Invert, of Vineyard Sd., etc., i). 293, 

 [592], pi. xii, figs. 62, 63, 1873. 



The female of this form was taken in Vineyard Sound, at surface, in 

 1875. Although agreeing in general with the male, it departs less widely 

 from the ordinary Heteronereis form, both in respect to its head, palpi, 

 and the dorsal parapodial appendages. The male has a simple, median, 

 tapering, caudal cirrus. There are two minute, dark spots on each seg- 

 ment, along the middle of the ventral surface, posteriorly. 



It is so nearly related to the Heteronereis stage of Nereis BumeriU, and 

 to the Heteronereis 2Ialmgreni described by Claparede, and to other 

 related forms discovered on our coast by Professor Webster, that it 

 seems probable that its Nereis stage, when known, will be closely aUied 

 to N. BumeriU, and consequently should be referred to Nereis, or to 

 Leontis, if the latter be regarded as a distinct genus. 



Ceratocephale Websteri, sp. nov. 



Head small, with the cephalic lobe emarginate in front, and with a 

 median groove running back; sides slightly incurved; posterior margin 

 slightly convex. No eyes. Antennae small, slender, tapering, coales- 

 cent at base with the palpi. Pali^i small, slender, bent somewhat down- 

 ward, not much larger than the antennte, the terminal joint small, sub- 

 acute, about one-third the whole length. The four cephalic organs are 

 similar in form, and all are directed forward. Tentacular cirri slender, 

 acute ; the dorsal ones of the two anterior pairs are longer than the 

 others, being nearly twice as long as the diameter of the body ; the ven- 

 tral ones are bent downward and forward in life, and are less than half 

 as long ; of the two posterior pairs, the dorsal are somewhat longer than 

 the ventral. 



