170 THELEPUS OINCINNATUS. 



In a preliminary account of a species of Streblosoma from the " Siboga " Expedition, 

 Caullery 1 reviews the genera of the Thelepinae, concluding with the following arrange- 

 ment : Fam. Terebellidae ; sub-fam. Amphitritea ; trib. Thelepina3; with four genera, viz., 

 Thelepus, Leuckart, Streblosoma (Malmgren 1867, Sars 1871), Euthelepus, Mcintosh, 1885, 

 and Parathelepus, Caullery (= Thelepides, Southern). Streblosoma he substitutes for 

 Grymcea, Malmgren, since the name has been preoccupied in the Protozoa. He separates 

 the four genera thus : 



Branchial filaments more ( se £ ment 2 (««* branchiferous), 



or less numerous. J nooks commence on segment 5 . Streblosoma. 



Bristles commencing on ' se ^ ment 3 ( second branchi- j segment 5 . Thelepus. 



[ ferous), hooks begin on 1 segment 11 . Parathelepus. 

 Branchial filaments, few, cirriform. 

 Bristles begin on segment 3, hooks on segment 5 Euthelepus. 



An interesting feature is the tendency in some species of Streblosoma to form a 

 spiral tube. 



So far as can be noticed in examples of Thelepus cincinnatus, Fabr., from Greenland 

 and Canada, the branchiae seem to arise on the second segment in both, a single clear 

 segment occurring between the collar and the first row of branchiae. Only two pairs of 

 branchiae are present in each. 



1. Thelepus ctncinnatus, 0. Fabricius, 1780, var. Andreanse, var. nov. Plate CXX, 

 fig. 1 — reproduced tail; Plate CXXVI, figs. 6 — 6d — bristles and hooks. 



rific Characters. — Dorsal cephalic collar with eye-specks; supra-oral arch and 

 ventral fillet small. Tentacles long, powerful, deeply grooved and crenate. Body about 

 6 or more inches long, typical in outline, and ending in a slender tail with the terminal 

 anus, which has about a dozen papillae at its margin. Segments about 100. Dorsal 

 surface rugose, glandular, with scattered papillae and often reddish-brown dots. 

 Colour reddish or pale orange inclining to yellow. Branchiae two on each side and 

 consisting of simple filaments often wavy from a slight spiral arrangement, the anterior 

 forming a longer transverse row than the posterior. Papilla on segment 4 under the 

 setigerous process and on 5, 6 and 7 between the latter and the torus. 



Setigerous processes numerous, commencing on the third segment, but ceasing a 

 considerable distance in front of the anus. Bristles of moderate length, in two series, 

 a longer and shorter, the tapering tips having narrow wings. Rows of " retrograde " 

 hooks begin at the posterior border of the fifth segment, comparatively short at first, 

 then increase in length anteriorly, remain nearly uniform for a considerable distance and 

 gradually become elevated, so that at the twenty-fifth a prominent uncinigerous process 

 is formed. Posteriorly as the bristles diminish these processes increase in prominence, 

 and finally as the uncinigerous processes diminish, they slant to the ventral surface 

 and cease at the anal segment. The hooks present a main fang and two teeth above it 



1 ' Bull. Soc. Zool. France/ t. xl, p. 44, with text-figs. 



