EUMENIA CRASSA. 39 



corethrura is the epitokous form of the sedentary Scalibregma, in which, both in the 

 ordinary and epitokous condition, he found some pigment-spots in a straight row on the 

 upper side of the dorsal cirri. His largest example was 85 mm. in length, or about 10 mm. 

 more than the fine Hebridean specimen. Michaelsen does not indicate the condition of the 

 reproductive elements. 



An orange or yellowish fragment of a Scalibregma procured between tide-marks, 

 Lochmaddy, August, 1865, represents the tip of the tail, which is terminated by a distinct 

 dorsal anus, and below it are a pair of anal cirri, the bases of which are close together, 

 that is, each springs close to the middle line, and in the preparation are comparatively 

 short, slightly clavate and curled upward at the tip, but of course this condition may 

 partly be due to the preservative fluid. The foot on this terminal region of the body has 

 a considerable and thick dorsal cirrus and a shorter ventral cirrus, with a small conical 

 elevation between them bearing open bristles, which are furcate, one of the limbs being 

 much longer than the other. No simple bristles are visible. 



Certain differences thus exist between this fragment and Scalibregma, though the 

 thick cirri had coloured cells internally, and on the whole approached it. The two cirri 

 may be new developments, the parts having been injured. 



Genus LXXXVII — Bdmenia CErsted, 1843 (including Lipobranchius). 



Head bilobed, with a short lateral tentacle on each side. Body short, sub-fusiform 

 or maggot-shaped. Segments three-ringed. No anal cirri. 



Subramose gills present or absent. Feet represented by two isolated, bluntly 

 conical papillae, bearing the capillary and furcate bristles. No cirri. 



OErsted (1843-4) thought that this genus made an easy transition from the Aricise 

 to the Telethusae (Arenicolidse), and it formed one of the genera of his Aricise lumbricinae. 



De Quatrefages (1865) instituted a new genus for E. crassa, viz. Polyphysia, to 

 indicate the varied relationships of this form. He did so on the ground that Eumenia 

 had been used by Risso for a genus pertaining to the Phyllodocidas. 



1. Eumenia crassa, CErsted, 1843. Plate CIII, figs. 5 and 5 a — bristles. 



Specific Characters. — Head conical with two lateral processes or tentacles. Body 

 about 2 in. long, rounded, somewhat fusiform, thickest anteriorly, slightly tapered 

 posteriorly. First six bristled segments bear branchiae each in the form of a thick cluster 

 of filaments springing from a central stem and in front of the foot, which (foot) consists of 

 a lanceolate lamella dorsally and ventrally, and a fan of simple and forked bristles, the 

 feet being continued from end to end. 



Synonyms. 



1843. Eumenia crassa, CErsted. Annul. Danic. Consp., p. 47. 



1844. „ „ idem. Arch. f. Naturges., Bd. x. p. Ill, Tab. iii, figs. 17—20. 



