36 Prof. M'Intosli's Notes from the 



far as could be ohserved, the general arrangement and number 

 of the setigerons and uncinigerous processes agree with 

 those of P. avrantiacus. 



The anterior setigerons processes, •which commence on 

 the second segment, appear to have a slightly longer posterior 

 papilla dorsally than in the former species, but the bristles 

 are similarly arranged in a longer and shorter sei'its, the 

 latter being more numerous ventrally. The bristles are 

 devoid of wings, are translucent pale golden, and in lateral 

 view present a slight enlargement before tapering to the 

 delicate tip, which is slightly curved. The shorter forms 

 have a more attenuate hair-like tip, and also present a trace 

 of an enlargement below it. The posterior bristles arc 

 shorter, more slender, and fewer in number in the small 

 tufts. 



The uncinigerous processes commence about the ninth 

 hristled segment, and occur in a single row. Anteriorly 

 the hooks are small, have a much shorter base than in 

 P. aitrantiaais, and the inferior outline rises into a con- 

 vexity behind the slender prow, while posteriorly it juts into 

 a process. Two or three teeth occur above the main fang, 

 and a distinct process projects from the anterior outline 

 just beneath it. The depth of the Ijase posteriorly and its 

 abrupt slope to the prow give a character to the hook. 

 Comparatively few seem to be in each row. 



The twenty-first form, Ereutho smitti, Malmgren, is 

 another extensively distributed species in which the cephalic 

 region is characterized by the absence of a distinct dorsal rim, 

 the smooth spout-like supra-oral fillet passing forward in the 

 median line, and, each side bending downward, forms a 

 broad rounded flap at the ventral edge, the arrangement 

 being symmetrical. The external margin curves outward, 

 and iipward — almost to the dorsal edge, — then doubles 

 sharply backward as a fillet and ceases. When the neck is 

 viewed from the dorsum these fillets are conspicuous on each 

 side. From the entire surface of this cephalic plate arise 

 the dense mass of bright yellow tentacles which form in- 

 extricable coils both in life and in spirit, and from the 

 edges of the lateral flaps are many small filaments. They 

 are mobile grooved organ.s ca[)able of endless changes — 

 now flattened and again rounded, coiled and twisted in 

 various ways, or again corrugated and wrinkled. The body 

 is pulled along by these organs which move like linear 

 Neraerteans over the glass. The tentacles in life show a pale 

 central streak under a lens, and their sides are dotted with 



