Oatty Marine Laboratory, St. Andrews. 21 



and the margin passes externally and veutrally to join the 

 anterior fold^ though it does not run evenly into it, a notch 

 or a fold separating it from the raised anterior fold, which 

 sometimes has a median projection with symmetrical lateral 

 curves, or in others sliglit fiills. This anterior or su[)ra-oral 

 fold does not project so far forward as in many Terebellids, 

 and it sometimes shows an inner fold over the mouth. The 

 pale orange tentacles seem to be of moderate length and 

 grooved, but are somewhat more slender and tapered than 

 in ordinary Terebellids. Below the mouth is a well- 

 developed tongue-like process, which pushes the rim of the 

 first segment backward when it projects, and veutrally it has 

 a narrow rim. 



The body is comparatively short, and in the preparations 

 is less dilated anteriorly than in the ordinary Terebcllid. 

 It tapers posteriorly to a slender tail with a terminal anus, 

 which has four large rounded papillse, two dorsal and two 

 slightly more prominent ventral. Dorsally the body is 

 rounded, veutrally flattened at the shields in front, and then 

 gi'ooved throughout the rest of its extent. Anteriorly 

 behind the dorsal collar the setigerous papillae approach the 

 median line, where a bifid process occurs in front of them, 

 and from the sides of the divisions the branchial stem 

 originates — not always in the same place, for in some tlie 

 right branchia springs antero-laterally in regard to the 

 right process, whilst the left branchia arises behind and to 

 the left of the left process. The free margin of the first 

 segment forms a continuous fold ventrally, which ends 

 dorso-iaterally in a rounded free flap, and a process is con- 

 tinued dorsally beneath its edge to the representative of the 

 setigerous process, which lies immediately behind the bifid 

 cone formerly mentioned. The next segment ventrally 

 has a large free lateral flap on each side, whilst the median 

 is differentiated into a narrow scute. The following seg- 

 ment has a still larger lateral flap, which stretches further 

 outward and upward and almost touches the base. of the 

 branchial stalk in the preparation. It thins off toward the 

 narrow scute in the mid-veutral line. Laterally it ensheaths 

 the lamella in front of it. 



The ventral scutes are about seventeen in number, besides 

 four or five small terminal median scutes, and after them a 

 median groove with a raised line continues to the posterior 

 end. Behind and above the third and fourth bristle-tufts 

 a smoothly-rounded process or long papilla occurs, and in 

 some two are found behind the fourth. In the Irish 

 examples they are clavate. Occasionally a smaller papilla, 

 occurs behind the fifth. 



