246 CIRRATULITS TENTACITLATUS. 



neck curves backward, then forward at the tip, and probably is the main agent in 

 giving the animal a firm hold of its burrow. Their appearance in the dorsal division 

 is somewhat late, viz. between the ninety-first and ninety-fifth. In both cases the fore- 

 going figures differ from those of Marenzeller and De St. Joseph. Marenzeller states that 

 the first ventral hooks appear in G. tentaculatus between the thirty-third and forty-fifth 

 segments, and the dorsal between the fortieth and sixty-fourth, whereas in Girratulus 

 Ghiajii the ventral appear between the twenty-first and twenty-third, and the dorsal 

 between the fortieth and forty-fourth. The great variation in the appearance of these 

 structures in British examples of G. tentaculatus would also, as De St. Joseph observes, 

 lead to some doubt as to specific identity based on this feature. 



An examination of two examples of Girratulus (Audouinia) filigerus from Naples 

 shows that in one the anterior tentacles arise less definitely than in G. tentaculatus, it 

 being difficult to say whether they are mainly opposite the sixth or the seventh bristles, 

 whereas in the other they are more like those in G. tentaculatus in regard to transverse 

 arrangement, and they arise opposite the fifth pair of bristles. In both a branchia springs 

 in front of the dorsal of the first series of bristles. The first ventral hooks occur on the 

 thirtieth bristled segment on the right in the first referred to, and the first dorsal hooks 

 on the forty-first ; whereas in the other example, with the groups of tentacles opposite 

 the fifth bristles, the first ventral hook occurs on the nineteenth bristled segment, and 

 the first dorsal hook on the thirty-seventh. These hooks are slightly less curved toward 

 the tip than those of the northern form, but otherwise are similar. The bristles are 

 proportionately longer than in G. tentaculatus. 



Fragments from the middle of the body appear to be able to reproduce a head 

 and tail, the broad ruptured ends contracting and the respective parts gradually 

 developing. When about an inch of the tail of a large form is broken off a cephalic 

 process buds out from the dorsum of the anterior end, and the alimentary aperture is 

 contracted. 



Habits. — When several are placed in a vessel of sea-water they immediately roll 

 themselves together, entangling mud and other animals present — forming a mass difficult 

 to unravel. In their native sites the long threads stretch themselves in every direction 

 in the mud, which seems to be the most fitting medium, since it keeps the filaments 

 apart; whereas in pure sea- water the animals appear to be less comfortable. They also 

 occur in the fissures of aluminous shale between the tide-marks. Like C. cirratus it 

 frequently enters empty tubes of other forms. Thus two small examples so fixed them- 

 selves in the tube of a Serpula that even after immersion in spirit the wall of the tube 

 had to be broken before they could be removed. 



This annelid would seem to be less eagerly devoured by fishes than the majority. 

 When placed in a tank with Gotti and flounders, the former seized it as it descended from 

 the surface, and, after a few seconds, ejected it, whilst the flounders only gazed at it. 



Reproduction. —In the middle of May examples at St. Andrews were loaded with dark 

 greyish ova, 0-1143 mm. in diameter. Males toward the end of June discharged from 

 the posterior region of the body a vast cloud of minute sperms with globular heads and a 

 slender posterior process or " tail." The heads are much more minute than those of Enlalia 

 viridis. At Naples Lo Bianco (1909) gives the period of sexual maturity as from June to 



