122 Prof. M'lutosh's Xotes from the 



the central aims at the bottom of the funnel, the aperture 

 being thus surrounded by a regular series of folds. The 

 gut was filled with the reddish mud amongst which the 

 animal dwells, and the massive tube was formed of the same 

 material with secretion. 



The tubes are massive, like those of Maldane sarsi, and 

 composed of mud lined by secretion. 



A fragmentary Isocirrus? which was dredged by Dr. 

 Whiteaves in 1872, in 125 fathoms off Capa Rosier, Gulf of 

 St. Lawrence, Canada, appears to agree with the Isocirrus D 

 in the structure of the hooks. The presence of the anterior 

 end, however, shows certain differences which call for 

 remark. The anterior end is characterized by its obliquity, 

 the cephalic plate commencing far back dorsally, and 

 sloping gently to the median frontal process, which is short 

 and broad. The rim is not much developed, and instead of 

 a notch has a lateral fold behind, which the unbroken margin 

 has a tendency to fold inward on the plate. Nearly 

 opposite the lateral incurvation of the rim a furrow passes 

 transversely inward to the keel, which is chiefly developed 

 in front of it, though there is a trace behind it. The keel 

 dilates a little behind the mid-frontal process which it joins. 

 The nuchal grooves pass forward by the sides of the keel, 

 and debouch at each side of the mid-frontal process. The 

 surface of the cephalic plate behind the transverse furrows is 

 marked by transverse lines. The mouth is partially open as 

 an ovoid area, having in the centre two lateral processes of 

 the proboscis with a longitudinal slit between them. 



The first segment is short, though a tuft of bristles of the 

 two kinds is present, but no spine could be seen on either 

 side. The second foot bears a short row of hooks which 

 agree with the typical form, except that the gular bristles 

 seem to be absent. The third and fourth also has well- 

 developed hooks and bristles. The intestine of this form 

 contained fine greyish mud in which were diatoms, radio- 

 larians, and othej- debris. 



A form (^Praxillella collaris, Claparede) dredged oif Orphan 

 Bank, Gulf of St. Lawrence, in 1873, differs from 

 Praxillella prcetermissa in the structure of the cephalic plate. 

 Thus the central anterior process is thicker and more 

 rounded than in the species mentioned ; the rim between it 

 and the lateral notch is more prominent in comparison M'ith 

 the posterior border, which, moreover, is crenate and has 

 no median notch. The crenations are bioad and blunt in 



