SYLLIS SPONGICOLA. 199 



After swimming about it settles on a stone or on the bottom, and gradually the anterior 

 end develops a head, first after the Tetraglene type, then that of Ghdetosyllis, thereafter a 

 median and two lateral tentacles appear as in Syllis arnica. The Ioida stage follows, with 

 moniliform tentacles and cirri. 1 Moreover, he found that the head, if removed, could be 

 reproduced. The bud swims actively about and by-and-by discharges the sexual elements. 

 The long natatory bristles are moved by muscles — as in Autolytus. Malaquin found 

 only male buds in what he calls Syllis spongicola, and large female buds in 8. hamata. 

 Langerhans describes the sperms as reddish, and the eggs as violet. Lo Bianco 2 states 

 that Neapolitan specimens are ripe in September. In the sexual forms a pair of pigment- 

 spots occurs on each segment, and Malaquin considers that they are veritable eyes, with 

 refringent granules and rods, vitreous bodies and pigment. 



This is one of the many species science owes to the laborious Grube of Breslau, who 

 in 1855 described it from an orange-coloured sponge, at Triest. He recognized most of 

 its important features. 



The Nereis teticpla of Delia Chiaje (1829) is either this or an allied species somewhat 

 approaching Syllis armillaris, he says, in general outline. 



Claparede (1868), in the specific description of this form (his S. hamata), observes that 

 the dorsal cirri are slender and short, not attaining the diameter of the body. The form 

 of the hooks he associated with its habits in tubes amongst Balani. He was uncertain 

 whether it bored such tunnels or took advantage of those of Polydora and other forms. 

 He thought it different from Grube' s S. spongicola, though the grounds for his opinion do 

 not now seem to be sufficient. He mentions glands with transparent processes (boyaux) 

 near the bases of the dorsal cirri. 



The Syllis setubalensis of the ' Challenger' 3 is probably only a variety of this species. 



A variety (tentacnlata) was found by Marion (1879) at Marseilles, having rather long 

 tentacles. He gives a goocl figure of the extended proboscis with ten soft papillae and the 

 median tooth, which seems to be large. 



Verrill figures a Syllis spongiphila in the collections of the ' Albatross,' which seems 

 to approach this species, but no description has yet been studied. 



Langerhans (1879) considers this a representative of one of the oldest and simplest 

 forms amongst the Syllidse. 



Marion and Bobretzky pointed out 4 the identity of Syllis hamata, Claparede, with 

 Grrube's species. They mention that the young are transparent (translucent ?), whereas 

 the adults are opaque orange. 



Albert (1886) has given a detailed account of the budding of this form at Naples, 

 the stolons occurring posteriorly from the thirtieth to the sixty-third segment, the bud 

 being broader than the nurse-stock, furnished with a pigment speck (ocular ?) at the base 

 of the dorsal cirrus, and containing either ova of a violet hue or sperms. The bud is 

 thrown off without a head but with long swimming-bristles. The author notes the 

 degeneration of the muscular walls of the body, the shrinking of the alimentary canal, 



1 All these are but stages of one process. 



2 ' Mitt. Zool. Stat. Neap./ xiii, p. 486. 



3 ' Annel "Challenger," ' p. 195, pi. xxx ; figs. 5 and 6; pi. xxxiii, fig. 6 ; and pi. xv a, figs. 16, 17. 



4 Op. cit. 



