GLYCERA. 187 



Glycera ca^itatSiyOerst. Annul. Dan.DorsibrA4.tah.7. f. 87,88,90-94, 



96 & 99. 

 Nereis teres, Dalyell, Pow. Great, ii. 144. pi. 20. f. 1, 2. 

 Nereis Sorex, Leach, Mus. 



Hab. The littoral region, burrowing in sand. 



Besc. Body vermiform, round, or rather somewhat flattened on 

 the ventral surface, tapered anteriorly to a sharp point, less tapered 

 at the tail, 2\ inches long, smooth, indistinctly annular, of a yellowish- 

 white colour, stained with the contents of the intestine, and marked 

 with a red vessel down the back. Head cornute, the apex sur- 

 mounted with four minute antennae only visible with a magnifier. 

 Proboscis very large, faintly striate in a longitudinal direction ; the 

 teeth brownish-black, corneous, falcate, divided into three processes 

 at the base, inserted into a sort of tubercle forming a square round 

 the plain oral aperture. Segments very narrow, equal and nume- 

 rous. Feet papillary, obscurely biramous, obtuse, pointed above 

 at the outer angle ; the cirri short, the inferior almost obsolete : 

 bristles colourless, jointed near the apex ; the spines straight, seta- 

 ceous, pellucid. Anal segment rounded, apodal, terminated with two 

 minute styles, which are frequently cast off in the animal's struggles. 



"Worm about 2" long, 1^'" broad, narrowed posteriorly, convex 

 and nearly alike on both surfaces, of a uniform dirty-white colour, 

 dusky about the head, which is cornute as usual. Proboscis clavate, 

 very villose, armed with black jaws. Feet lobulate, alike ; the upper 

 lobe ? large, conoidal, more prominent than the inferior, which is 

 about half the size and apiculate ; superior ? lobe with a short cirrus 

 not reaching to the point, and armed with two sets or fascicles of 

 bristles kept asunder by the apex : bristles compound, bayonet- 

 like, the top-piece often broken off, colourless ; spine one to each 

 lobe, setaceous, colourless. 



Glycera capitata lives under stones, sometimes buried in the gravel 

 or sand, but the worm never penetrates far below the surface. Its 

 motions in the water and in the sand are slow, but when irritated 

 the contortions of the body are violent, and it very often twists itself 

 so as to form a short spiral column. 



Savigny considers his G. unicornis to be identical with the Nereis 

 alba of Miiller. It is more probable, however, that the British 

 species is the same as the Norwegian ; the more especially as there 

 is nothing in the description to create any doubts of their identity. 

 The G. unicornis is remarkable for its want of jaws, affording a 

 striking proof that organs of vast importance in the higher classes 

 are here only of secondary consequence, and do not even afford a 

 good generic character. 



Obs. Of a yellowish-white colour, smooth, and indistinctly seg- 

 mented, the segments narrow and numerous. 



(a) South Devon, G. Montagu. 



(5) Aberystwyth, J. Henslow. 



(c) Holy Island, Dr. Johnston. 



Plate XV. a. Fig. 1. Glycera capitata, natural size, and in a favourite 



