NEEEIDJE 



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Family X. — Nebeihe:. 



This family is characterized by the activity and muscularity of its members. The 

 head is well formed and bears eyes and prostomial tentacles. The cephalic ganglia and 

 nervous system generally are highly developed. The palps are massive and two-jointed. 

 The chitinous buccal membrane is continuous with that covering the proboscis, which in 

 extrusion is readily divided into two regions, and armed with a pair of horny jaws and a 

 series of horny teeth (paragnathi), which after Kinberg may be arranged in eight groups, 

 as in the accompanying outlines from Nereis pelagica (Figs. 58 and 58'). 



Figs. 58 and 58'.— Outlines of the extruded proboscis of Nereis pelagica, the dorsal surface being on the 

 left, the ventral on the right, a. Maxillary region, b. Basal region. The areas of the parognathi are 

 in Roman numerals, viz. — I, unpaired median dorsal maxillary ; II, lateral dorsal maxillary ; III, unpaired 

 median ventral maxillary; IV, lateral ventral maxillary; V, dorsal unpaired median basal ; VI, dorso- 

 lateral basal; VII, ventral unpaired basal; VIII, ventro-lateral basal. 



The alimentary canal behind the proboscis is cylindrical and is furnished with a pair 

 of glands. This is followed by a more or less simple straight intestine. 



The body is elongated, rounded or somewhat flattened, segments similar, the first 

 devoid of feet, but with two tentacular cirri on each side; the feet are usually biramous 

 and nearly alike throughout, though the first two are simple and the caudal somewhat 

 modified. It terminates in two cirri beneath the vent. 



The body-wall (Fig. 59) in this family is surrounded by a well-developed cuticle with 

 a considerable thickness of hypoderm beneath. The latter coat is bounded internally 

 by the basement-membrane, within which is the circular layer of muscular fibres. The 

 dorsal longitudinal muscles in transverse section are lappet-shaped, that is, massive 

 externally and inferiorly, and thinning off towards the raphe in the mid-dorsal line. The 

 ventral longitudinal muscles, on the other hand, have a characteristic dorsal and external 

 inflection with a somewhat pennate arrangement of the fibres, the ventral portion of the 

 muscles being spindle-shaped. The inner ventral band of muscular fibres from the bases 

 of the spines passes to the exterior of the curvature of the ventral longitudinal muscles. 



1 Lycoridea, Savigny, Griibe, Elilers, etc. 



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