88 Prof. M'IntosIi's Notes from the 



So far as these parts show, three segments would thus 

 seem to pertain to the collar-regioUj viz. that of the second 

 long cirrus and the two branchial segments. 



The next region of the body consists of three bristled seg- 

 ments, devoid of hooks as in allied forms. The appearance 

 of these, however, suggests a subdivision, for the two anterior 

 have ihe thick glandular ridges, the first with a single central 

 division and the second with two central divisions; Avhereas 

 the third ha^ only a long, slender, non-glandular ridge, as in 

 those which follow. This region appears to be, on the whole, 

 considerably foreshortened in contrast with Lagis. The 

 first two tufts are very small, and they arise from the non- 

 glandular or dorsal part of the ridge. The third is consider- 

 ably larger, and is usually closely applied to the surface of 

 the dorso-lateral region. Each tuft has the stout, tapering, 

 simple bristles with traces of wings distally below the 

 tapered point, and all have, in addition, a few in which the 

 spear-like dilatation at the tip is present, with its tapering 

 hair-like point and serrated edge. All these bristles have a 

 peculiar ring-like dilatation at the base. 



The third region is characterised by the great development 

 of the lateral lamelhe for the hooks, as well as for the long 

 and powerful bristles at the dorsal edge. All the latter are 

 very powerful anteriorly, dilating from the base upward 

 until full diameter is attained, and then tapering to a delicate 

 hair-like tip. Besides these are the bristles with the spear- 

 shaped enlargement and the finely tapered tips, the shafts 

 being also robust. The posterior bristles are considerably 

 smaller, but they keep to the same type, those with the 

 spear-shaped tips being proportionally longer. 



The caudal hooks are situated on each side of a small keel 

 (notched at its free end), which marks the median dorsal 

 region of the caudal appendage. They are distinguished by 

 their comparatively great length and straightness, by the 

 rapid diminution at the neck, and by the abrupt curve and 

 sharp condition of the hook at the tip. The edge of the 

 jjrocess is deei)ly and symmetrically notched, usually curved 

 ventrally, and the dorsal lip of the vent is prolonged as a 

 somewhat flattened conical process, with a dorsal papilla on 

 its surface, which curves beyond the split vcuti-al lip. The 

 dorsal surface of the process is concave, forming a deep 

 groove, whilst the ventral is convex and grooved by oblique 

 furi'ows directed outward and backward. It seems to be 

 easily regenerated, even before the bristled segments neces- 

 sarv to complete the series are formed, and thus some 

 examples arc jjciuliaily short and broad, theta])cred posterior 



