AMPHITRITE FIGULUS. 121 



apparently taking place during their growth , groups of three after division occasionally 

 occurring. On reaching the full size division seems to be rare. Each large cell has 

 a cell- wall which sometimes is ruptured or dissolved, and the coarse granules form a 

 botryoidal surface. 



Reproduction. — In May the pale salmon-coloured ovaries occurred in the anterior 

 region, extending to the seventh or eighth bristle-tuft as a series of lobate folds crowded 

 with very minute ova. The nephridia are large and numerous. In the same month 

 (May) a large example had in the ccelomic cavity a quantity of a dull purplish gelatinous 

 fluid, the colour being apparently due to the minute granules of purple oil in the ova, 

 which measured *046 mm. in long and '037 mm. in short diameter. There were besides 

 numerous ccelomic corpuscles, elongated or spindle-shaped bodies, which by-and-by 

 disappeared from the fluid. 



Habits. — It is less active than T. nebulosa, and lies rolling in a vessel moving branchiae 

 and tentacles. Dalyell says it is phosphorescent, but this has not been observed at 

 St. Andrews. 



The tube in a Hebridean example is earthy and rather friable. In confinement it 

 rapidly forms a membranous tube in the vessel of sea- water, both ends of the tunnel being 

 open. From this shelter it stretches its attenuated tentacles along the bottom. In 

 tangle-roots the tube is formed of mucous lining with sandy mud externally. A tube 

 from Bantry Harbour (E. I. A. Expedition, 1885) consists of mud and dark fragments 

 like peat, the whole forming a thick friable coating. At St. Andrews the tubes are 

 composed of sand-grains and mud (and they retain their shape), part being attached to 

 stones and part to the mud beneath. In one instance the tube was a foot and a half in 

 length, and contained in addition the commensal, Gattyana cirrosa. 



Commensals. — The ordinary commensal at St. Andrews is Gattyana cirrosa, though 

 at least on one occasion large examples of Sthenelais boa were obtained near the mouth of 

 their tubes at low-water mark. De St. Joseph found the former also in the tubes on the 

 shores of France (Croisic). 



If Montagu's Terebella constrictor proves to be this- form, then his title has priority. 



Dalyell's (1853) description and figure are perfectly clear, so that there is no 

 dubiety as to the species which he called the potter from its predilection for mud in the 

 construction of its tube. He pointed out the thick, heavy and friable nature of the tube in 

 contrast with that of Lanice conchilega, and the fondness of the annelid for empty shells 

 in deep water. A small specimen which from injury had only twelve bristle-tufts, 

 regenerated its body in five or six weeks. The versatility of the annelid, he noted, 

 was surprising. "Many tentacula are searching for materials, many in collection, 

 many bearing them to the edifice, some quitting their hold, others recovering the 

 load, while the architect itself seems occupied in kneading masses in its mouth, dis- 

 gorging them successively, or in polishing the rude workmanship resulting from its 

 labours." 



So far as can be gathered from Claparede's description and figures (1870), his 

 Amphitrite nana would not appear to offer substantial differences from this species. 



Cunningham and Ramage (1888) state that there are fifteen to seventeen pairs of 

 nephridia in the first fifteen to seventeen post-buccal segments, and that there are median 



185 



