30 SCALIBEEGMID^J. 



as a rounded, ringed sac to the posterior end, where a slight diminution occurs before the 

 abrupt termination. It is closely ringed, and the anterior dorsal surface presents the 

 tesselated condition characteristic of Scalibregma. A trace of a median groove exists 

 ventrally. The feet are represented by a pair of minute papillas every third ring, but no 

 bristles could be found. It terminates posteriorly in a short, almost cylindrical, process 

 with a fissured edge. 



Synonym. 

 1908. Travibia Gravieri, Mcintosh. Ann. Nat. Hist., 8 ser., vol. i, p. 383. 



Habitat. — Dredged in 539 fathoms in the ' Porcupine ' Expedition of 1870, Station 

 No. 9. 



A small form resembling the larva of one of the Diptera, and measuring about 5 mm. 

 in length. The snout terminates in a smooth pointed process, the body gently dilating 

 thereafter, and continuing as a rounded, ringed sac to the posterior end, where a slight 

 diminution occurs before it somewhat abruptly terminates. The rings in the contracted 

 posterior region encircle the body to the central cylindrical caudal process, which is 

 fissured or crenate at the tip. The dorsal surface is convex ; the ventral concave from 

 before backward. The body is closely ringed from the base of the prostomium to that 

 of the caudal process, the anterior dorsal surface especially showing the tesselated 

 condition characteristic of Scalibregma, but the ventral surface is smoother, and has in 

 the middle line a faint trace of a -groove. The posterior rings have a crenate posterior 

 edge. 



At first sight feet appear to be absent, but close inspection shows a pair of minute 

 papillse in a row every third ring. 



Two of the minute feet were examined, but no bristles were found, though a slender 

 papilla, slightly tapered at one end and apparently ciliated, occurred in connection with 

 the foot, but whether external or internal is unknown; certainly no trace was seen externally 

 under a low power. The degeneration of the feet is in this form carried out almost to 

 their disappearance. 



Family XVI. — ScALiBitEGMiDiE, Malmgren, 1867. 



This family approaches the Arenicolidae in various respects, such as the somewhat 

 tesselated condition of the skin anteriorly and the limivorous habits, but the distinctions 

 are nevertheless evident. The prostomium is small, either with or without short lateral 

 processes, and has the lateral nuchal grooves through which the nuchal organs may be 

 protruded. Eyes are usually absent. The body is comparatively short, sometimes 

 enlarged anteriorly or fusiform in outline, and gills, when present, are generally anterior, 

 and few in number (four to five). The segments are annulated, the dorsal and 

 ventral divisions of the feet are nearly equal, and carry long, simple, and shorter, forked 

 bristles, whilst between them a protrusible sense-organ exists. The pharynx is smooth, 

 and the alimentary canal simple, terminating in an anus with or without cirri. The 

 heart is median, and is an enlargement of the dorsal vessel. Narrow ciliated nephridia 

 occur in almost all the segments. 



