Gatty Murine Laboratory ^ St. Andrews. hi 



Whether this is an example with the anterior region in 

 course of reproduction or a variety is uncertain, but its 

 features are worthy of note. 



Myxicola viridiSj Mihie-Edwarcls, the twenty-second 

 species, occurred in the mud of a mass of Filoijrana pro- 

 cured off the Bell Rock, St. Andrews Bay. Tlie cephalic 

 region seems to agree with that of M. itifundibulum both 

 in the absence of a collar and in other respects. 



The braucliice form a rich green spiral mass in repose, a 

 position often assumed in its sheath under examination ; but 

 when it protrudes, the anterior end of the branchise spread 

 out as a double fan of nine or ten filaments, which have a 

 chordoid axis and a terminal process, which differs from the 

 tapering elongated one of M. infundibuliunm maintaining its 

 strap-like breadth till near the tip, where a short tapered 

 region occurs. The body is capable of considerable elonga- 

 tion, and the total number of segments is about forty- seven, 

 eight anterior and thirty-nine posterior. A well-maiked 

 papilla at the anus terminates the body posteriorly. The 

 colour is a rich green, the central interspace being darker. 

 The first pair of bristle-tufts has a different direction from 

 those which follow, being directed obliquely forward and 

 outward. The anterior bristles are the most conspicuous — 

 indeed, in a specimen so minute tiie posterior at first escape 

 notice. The typical anterior bristle has a slender translucent 

 shaft and finely tapered tip and narrow wings. The poste- 

 rior bristles are more minute and the wings less distinct. 

 Many present a curvature at the commencement of the tip. 



The anterior hooks are in groups of five or six, and are 

 long /-shaped structm-es which resemble somewhat those of 

 Oligochsets. The wide region or shoulder is in front of the 

 middle, the shaft tapering posteriorly to the base and ante- 

 riorly to the long neck, which is almost straight. The main 

 fang leaves the neck nearly at a right angle, and is short and 

 sharp, and on the crown above is a single prominent tooth. 

 The whole organ thus characteristically difters from that of 

 M. infundibulum. The posterior hooks are miuute, having a 

 long sharp main fang, and another above it almost as long, 

 a nearly straight posterior outline, and a short base directed 

 forward. The annelid secretes a transparent gelatinous tube 

 in captivity. 



At least two species of Myxicola thus inhabit British 

 waters ; but, in regard to the green example, it may be a 

 question whether it is not a marked variety, with more 

 transparent branchia3, of the tvpc with the minute bifid 



-t* 



