192 SYLLIS KROHNII. 



The foot (Plate LXX, fig. 17) lias the dorsal cirrus crenate rather than moniliform, 

 and tapered. It arises from the dorsum without a distinct basal region. The setigerous 

 lobe is bluntly conical, with the trend of the distal margin downward and slightly inward, 

 and having the usual furrow for the bristles. The two spines reach the surface at the outer 

 and upper angle and have distinctly hooked tips which point upward. The bristles (Plate 

 LXXIX, fig. 11) have strong translucent shafts with dilated and bluntly-bevelled ends 

 without evident serrations, though two spikes occur at the point. The terminal piece is 

 short, ending in a simple hook, occasionally with a minute spike on the edge. The ventral 

 lobe is broadly ovate and does not quite extend to the tip of the setigerous region. 



3. Syllis Krohnii, Elders, 1864. Plate XLIX, fig. 6; Plate LXXIX, fig. 12— bristle. 



Specific Characters. — Head notched in front, somewhat narrowed behind, and with 

 two prominent, tapering, ciliated palpi. Eyes four, reddish, placed obliquely in pairs, the 

 anterior being the wider apart. Median tentacle shorter than the lateral. It arises between 

 the eyes, and is speckled with white dots. The dorsal tentacular cirri are longer than 

 the lateral. All are slightly annulated and have white specks and whitish tips. Body 

 about an inch and a half long, little diminished in front, but tapering posteriorly to a slender 

 tail, with a median papilla and two lateral cirri. Dorsum pale anteriorly, with about a 

 dozen madder-brown belts, the anterior being double. Ventral surface pale anteriorly, 

 pale orange behind, and translucent towards the tail, which has two long cirri. Dorsal 

 cirri alternately large and small. Proboscis with a denticulated edge and a prominent 

 tooth. The setigerous region has a series of translucent bristles with a trace of serrations 

 on the convex edge of the distal enlargement of the shaft. Terminal piece of moderate 

 length with a simple hook at the tip and a finely spinous edge — the spine next the tip 

 being so prominent as to give a pseudo-bifid appearance to the tip. Ventral cirrus of an 

 elongated conical form. 



Synonyms. 

 1864. Syllis Krohnii, Ehlers. Borstenw., I, p. 234, Taf. x, f. 1—4. 

 1805. ,, „ De Quatrefages. Anneles, ii, p. 31. 



1869. „ „ Mcintosh. Trans. E. S. Edin., vol. xxv, p. 415, pi. xvi, f. 14. 



1881. Typosyllis Krohnii, Langerhans. Can. Annel., Nov. Act. Leop.-Car. Deutsch. Akad., xlh, 



p. 102 (?). 

 1885. Syllis „ Cams. Fanna Medit., p. 225. 



1906. Syllis (Typosyllis) Krohnii, De St. Joseph. Ann. Sc. Nat., 9 e ser., t. iii, p. 180. 



Habitat. — In a tube of sand under a stone in a rock-pool near low water at Paible, 

 North Uist. It may have crept accidentally into the tube, for it generally prefers to hide 

 itself under debris in a vessel. Between tide-marks, Herm. Benham 1 states that it is 

 abundant under stones, and forms tubes, but gives no locality. It is not common in 

 the author's experience. 



i f Camb. Nat. Hist./ ii, p. 307. 



