NERINE. 139 



Genus XCVI. — Neeine, Johnston, 1838. 



Nerine, Johnston ; Aonis, Andouin and Edwards ; (non Savigny) ; Spio, Johnston, 

 Rathke ; Lmnbricus, Belle Chiaje ; Malacoceros, Be Quatrefages. 



Snout (prostomium) with a rounded or acute point ; mouth with a massive proboscis. 

 BranchiaB from the second setigerous segment almost to the posterior extremity. Cup- 

 like anal structure. Integuments with bacilliparus follicles. Membranous lamella along 

 the branchia3, at least in the anterior segments, with capillary bristles only ; row of cilia 

 on both bases of the branchise. Feet biramous. Ventral lamella elongated transversely 

 after the thirtieth or fortieth setigerous segments, presenting a median inflection, then a 

 ventral lobe. Winged hooks both dorsally and ventrally, but in some they are absent 

 from the anterior rows. Eggs have a zona (chorion, Mesnil) with minute transparent 

 vesicles. All the species are of some size. Feed on Fuci and minute shells. 



In Nerine foliosa the pointed snout is completed by the intricate interlacing of the 

 muscular fibres beneath specially thickened cuticular and hypodermic layers. As soon 

 as the body-wall assumes a rounded form a layer of circular and oblique muscular fibres 

 occurs beneath the hypoderm, the majority having an oblique direction. The appearance 

 of the mouth, by the infolding of the muscular lip, alters the outline inferiorly, the 

 massive sides being fixed by muscular bands to the dorsal arch superiorly, whilst the 

 lateral area on each side is occupied by oblique and transverse fibres and numerous 

 ramified blood-vessels. Strong transverse bands of muscular fibres occur in the lower 

 lip, and grasp the various ridges on the inner surface of the canal. These fibres turn 

 upward at each side, and mingle with those of the upper lateral region, and some pass to 

 the dorsal wall. They thus constrict the aperture efficiently. A little behind the fore- 

 going the oesophagus is suspended in the centre of the area by strong muscular bundles, 

 the most conspicuous of which are vertical, passing from the basement layer beneath the 

 hypoderm dorsally to the oesophageal wall. A second series of fibres, as they descend 

 to their insertion at the ventral surface, give lateral support to the tube, whilst a third 

 group of fibres interlace in a complex manner, and with the blood-vessels, as in front, 

 fill up the space between the oesophagus and the body-wall. 



Toward the posterior part of the head a slight hypodermic prominence indicates 

 the position of the cephalic ganglia which lie outside the muscular layers. In a line with 

 the first bristles the circular muscular coat is better defined, though in the dorsal region 

 the fibres spread out at each side and mix with those of the vertical, a comparatively thin 

 layer crossing the middle line of the dorsum. Within the circular muscular coat dorsally 

 is a more or less developed longitudinal ventral layer — at first less definitely arranged, 

 but by-and-by grouped in three bands, viz. first, a thin median sheet between the wide 

 attachment of the vertical muscles, and a more powerful band stretching between the 

 outer margin of the vertical and the foot, and as the fibres of the oblique pass outward 

 and upward to the foot this section of the muscle is thus clasped in a special chamber in 

 various sections. The dorsal longitudinal muscles are already normal in position and 

 arrangement, the broader end of the muscle in section being external, the narrower 



