PLATYNEREIS POLYSCALMA. 225 



rior one and nearly contiguous with it. The anterior eye is much larger than 

 the posterior. The prostomium is dorsally mesally notched behind, a triangular 

 flap from the peristomium extending into or above the notch as in the male. 

 (Plate 31, fig. 1). 



The peristomium is very short as compared with the prostomium, but dor- 

 sally is clearly longer than the second somite. It is divided on each side above 

 by a transverse furrow which, toward the middle, extends forward along the 

 side of a triangular area into the before mentioned notch of the prostomium. 

 The tentacular cirri are strongly varicose or irregularly jointed, the joints being 

 very short. The dorsal tentacular cirri of the first pair are long; each is attached 

 immediately below the interval between the two eyes; the ceratophore very 

 short; the style gently tapered and reaching to the tenth or eleventh somite. 

 Each anterior ventral tentacular cirrus is attached below at the lateral border 

 of the mouth; it is subulate and reaches to the fifth somite. Each ventral 

 tentacular cirrus of the posterior pair is attached at nearly the same level as 

 the dorsal of the anterior pair; it is more slenderly tapered and reaches to the 

 eighth somite. Above it is attached the dorsal cirrus, but this in all the types is 

 broken off near the base at which it is as thick as or a little thicker than the 

 dorsal anterior one. The border of the mouth laterally and posteriorly is 

 broadly elevated and is strongly radially wrinkled. 



The anterior setigerous somites are very short. Above, each is divided 

 by a transverse sulcus, while one or more weaker sulci may occur caudad of this. 

 On each side just above the parapodium each somite is crossed by a conspicuous 

 series of longitudinal striae, these becoming weaker over the middle region of 

 the dorsum. Ventrally there is a similar dividing transverse sulcus on each 

 somite, this much more deeply impressed in the neural furrow and with faint 

 secondary sulci on each side showing especially laterally. The pygidium as in 

 the male; no anal cirri present in the types. 



Parapodia in general structure as in the male, but modified very differently 

 in the anterior region. In this region the neurocirri are attached on the ventral 

 side near the base; on the first parapodia they are relatively and actually thicker 

 and longer than on the others, not flattened; decreasing gradually caudad 

 until they are very slender and fall much short of attaining the end of the neuro- 

 podium, whereas in the anterior ones they equal that ramus. The notocirri of 

 tlie most anterior parapodia are stout and conspicuously long, extending much 

 beyond the notopodium; each narrows rather abruptly distally into a slenderly 

 cylindrical, distally pointed tip. Caudad the notocirri become smaller, as a 



