AMPHARETDLE. 



61 



identity is uncertain. A tube from 567 fathoms in the Atlantic in the " Porcupine " 

 Expedition of 1870 presents a uniform series of dull yellow grains throughout. The 

 rounded and comparatively large yellow stones forming a tube from a depth of 

 52^ fathoms (log 33) off the south west of Ireland are noteworthy. 1 



Family XXVIII. — Amphaeetim:, Malmgren, 1867. 



Cephalic lobe (upper lip of some) covering the mouth, the median part separated 

 by oblique grooves ; tentacles long, smooth, pinnate or ciliated, arising from the 

 mouth, and can be engulfed. Buccal segment surrounding the mouth and forming 

 the lower lip, occasionally biannulate. Tentacular membrane is divided by two longi- 

 tudinal grooves into three. A groove between tentacles and mouth. Body somewhat 

 broad in front, tapered posteriorly and with a variable number of segments, generally 

 twenty to forty, rarely about seventy, and of two regions, the anterior (or thoracic) 

 having fascicles of capillary bristles and pinnules for hooks, the posterior (or 



Fig. 143. — Transverse section of the body-wall of Ampharete Grubei, in the anterior region, cc, cardiac body ; 

 Gl.v., ventral glands ; La., anterior lobes ; Na., anterior nephridia ; Np., posterior nephridia ; Oe., oesophagus ; 

 Vv., ventral vessel. (After Fauvel.) 



abdominal) bearing only the pinnules for the hooks. Second segment provided 

 with palese or capillary bristles as in the third and fourth. Anal segment with 

 two cirri. Branchiae filiform or subulate, seldom pinnate, four, rarely three, on 

 each side, affixed to the anterior segments 2 and 3, and having in front the group 

 of paleas (palmulas) on the second segment — sometimes absent. Anal segment naked 

 or with two or more short cirri. The stomach is simple, as in the Amphictenidse, 

 the oesophagus having a lobe on each side. Diaphragm between the third and fourth 

 segments with muscular sacs which Meyer thought were for the lodgment of the tentacles. 

 Bristles capillary, tapered, with smooth extremities ; shafts arising on a cylindrical or 

 subcorneal tubercle (setigerous process). Reduced on the third segment. Hooks 

 commence on the sixth segment except in Melinna, uniserial, pectiniform, multidentate, 

 the anterior being absent in Melinna and Isolcla. Posterior feet with dorsal cirri. Tube 

 cylindrical, fragile, soft, longer than the animal, walls more or less thick, composed of 

 mud, fragments of algse, sand or minute stones. 



In the structure of the body-wall (Fig. 143), after it is completely formed, Ampharete 

 Grubei, as sketched by Fauvel, presents in the anterior region under the cuticle and 

 hypoderm continuous dorsal longitudinal muscles (apparently fused in the middle 

 1 Mr. Crawshay thinks Dr. GemmhTs note is the first in Britain, but such is not the case. 



