1910.] NATURAL SCIENCES OF PHILADELPHIA. 495 



The characteristic operculum ought to be readily recognized. It is 

 described, in the type, as concave, of a dull yellowish color with brown 

 rim; a second specimen has an additional upper part, like an inverted 

 cone. 



The peculiarities of the collar described as made up of a number of 

 unequal ribbon-like processes or lobes, are possibly due to injury. 

 The rectangular form of the thoracic uncini, with numerous teeth above 

 one long, sharp, terminal one, seems the only character showing any 

 affinity to the genus Placostegus (type, P. tridentatus) . The thoracic 

 setse are very slender and simple. The Placostegus incomptus Ehlers, 

 1887, from off Cuba, in 101 to 129 fathoms, has strong affinity to the 

 genus Plagostegopsis Saint-Joseph, 1894. 



Eucarphus serratus sp. now 



Branchial lobes not free, the branchiae arranged in a semicircle; 

 there are twelve about equal ones in each, with long delicate ends 

 and long pinnae; a rudimentary operculum opposite the fully developed 

 one, which has two chitinous cups one above the other, the lower with 

 numerous radii and deeply pointed margin, very unlike the shallow 

 broadly scalloped margin found in that of Eucarphus lunulifera 

 Claparede, 1870, the upper one edged with thirteen stout, rather long, 

 erect spines broadly rounded on the end, curved beneath on either side, 

 forming a small angular lateral point; no outer, inner, nor basal 

 processes or spinelets. Collar very deep and full. Seta? similar to 

 those found in Hydroides and Eupomatus, with stout manubrium 

 having two large tooth-like spines on exposed end at the base of the 

 very delicate, abruptly tapered terminal portion, not broadened into 

 a blade. Six fascicles of seta? and six tori on thorax. The setse with 

 long gracefully tapered ends; the uncini somewhat triangular in 

 outline, the base much prolonged and tapered beneath the teeth, which 

 number about seven, are of about equal size, rather long, pointed and 

 appressed, in front view appearing broad and delicately serrate in a 

 single series; on the abdomen becoming smaller and thicker with more 

 numerous sharper teeth, eight or nine in the largest, the last broader 

 than the others. Abdominal setse flaring, with coarsely serrate edge, 

 elongated on one side with a delicate (scarcely discernible) filamentose 

 end; needle-like along caudal region. 



Only one specimen in an irregular good sized tube roughened only 

 by unequal irregular lines of growth. 



This may prove to be the Eucarphus dirampha Morch , 1863, from 

 St. Thomas, W. I. 

 32 



