1903] NATURAL SCIENCES OF PHILADELPHIA. 457 



hooked setae; they are most numerous in the dorsal group (5-6 dorsal 

 and 2-3 ventral in the middle branchial region) and here persist the 

 longest; the knife-edge flange dehcately striated, widest at base, 

 diminishing toward tip, and leaving a very acute point, flange directed 

 dorsally in the ventral setae, ventral in the dorsal; shaft of setae bent 

 more or less strongly at the base of the flange and on the margins of 

 the bmidle, the tips often recurved in the opposite direction. Pos- 

 teriorly the lance setae become reduced to 2 or 3 in the dorsal bundle; 

 darker, even black, in color, straighter, more slender and with a much 

 reduced flange. 



The hooked setae of the anterior segments exhibit transitional charac- 

 ters between the lance-shaped setae and the posterior hooked ones. 

 Anteriorly they are pale yellow, posteriorly darker as they pass into 

 the more typical hooks, stouter than adjacent lance-shaped setae, but 

 of the same form until near the tip, when the shaft suddenly contracts, 

 bends slightly l^ackward and terminates in a short truncate hook, 

 bearing about five short teeth of diminishing size; at the same place 

 the flange forms a guard which includes the hook and conforms to its 

 shape. Posteriorly the hooks become darker, longer, the tip stouter 

 and more prominently hooked, the nimiber of teeth 7 or 8, of which 

 the most proximal is the largest, the blade absent except where it 

 forms the hood-like guard, and the stem club-shaped. 



Skin strongly iridescent, but color all gone. 



Only the type known from station 3,767, Sendai Bay, 14-18 fms. 



GONIADID^. 



Goniada (Leonnatus) foliacea sp. nov. (PL XXVI, figs. 75, 76.) 



The largest specimen measures 98 mm. long, 4 mm. between the tips 

 of the setae in the anterior region, and 5.3 mm. at the beginning of the 

 posterior region. The relatively stout body consists of 160 somites, 

 in addition to j^erhaps 3 or 4 which have been lost at the caudal end. 

 The posterior region, beginning at somite LXIII, is filled with 

 sexual products in the larger individuals and, being very readily de- 

 tached, may separate and swim independently at maturity. 



Head prominent but shorter than in most species, bluntly conical, 

 slightly depressed, length twice width, composed of only four strongly 

 marked rings, the basal one nearly equalling all the others in length, 

 and the latter decreasing to the tip, furrows on ventral and dorsal 

 surfaces alternating in position and joined by a jjair of lateral zigzag 

 grooves which terminate caudally in a small slit-like i)it on each side 

 of the peristomium. dorsal to the palpi. (.)n the ventral surface of the 



