THE ANATOMY OF SCALI BREGMA INFLATDM. 251 



being only G — 8 jli (fig. 25). The prongs of the fork are 

 sometimes straight, but more usually curved, their very fine 

 tips pointing away from each other. The two rami are not 

 quite equal ; in tlie largest specimens they are 50 — 65 n and 

 65 — 75 /J. in length respectively. The proximal portion of 

 the edge of each prong bears a uutnber of minute curved 

 pointed processes. 



In the large worm (56 mm. long) there are fifty to sixty 

 simple seta3, and about twenty to twenty-four furcate sette in 

 each ramus of the parapodium of the anterior half of the 

 animal. 



On clearing the posterior end of another specimen by 

 treatment with warm potash solution the very small setae 

 present in the newly formed parapodia are seen. Each of 

 the notopodia and neuropodia in this region bears only one 

 or two simple setee, accompanied by one furcate seta. Both 

 kinds of setas are therefore present in the parapodia through- 

 out life. 



Furcate setae were first discovered by Malmgren (1867, p. 

 187) in Euraenia crassa, and were shortly afterwards 

 observed by Mcintosh (1868, p. 419, and pi. xvi, fig. 5) in 

 Eumenia (Li pobrauchius) jeffreysii. Theel (1879, p. 

 49, and pl.iii,tig. 47a) figures them in Eumenia ion gise to s a, 

 and Hansen fl882, p. 34, and pi. v, figs. 16 — 19) in Scali- 

 bregma inflatum, S. {'^) parvum, and 8. (?) abyssorum ; 

 but the figures of these authors do not show the minute 

 barbules on the inner side of each prong. Mcintosh (1885, 

 pi. xxii J., fig. 21) saw the barbules on both prongs of the 

 forked sette of his southern specimens of S. inflatum, and 

 figured similar setfe from Eumenia reticulata (1885, p. 

 360, and pi. xxii ^, fig. 20), and S. Joseph (1894, p. 106, 

 and pi. V, fig. 133) has observed them in >Scleroclieil us 

 minutus. 



The furcate bristles of Eumenia glabra described by 

 Elders (1887, p. 170, and pi. xlv, fig. 4) ai-e remarkable for 

 the great inequality in length of the prongs, one being 

 nearly three times the length of the other. Elilers (1887, p. 



