6 MR. A. W. WATERS Ott THE MARINE 



the irregularity of the median avicularia, and this I can confirm from 

 Mediterranean specimens, in which some parts are without them, and others 

 have them fairly regularly. 



Loc. Naples, Capri, Rapallo, Trieste, Suez, Madeira ; Cape Verde Islands, 

 110-180 met. (Calvet), and St. Vincent Harbour, Cape Verde Islands, 

 10 fath., collected by Crossland. 



Scrupocellaria Macandrei, Busk. (Plate 1. figs. 3-7, 11.) 



For synonyms see Waters, "Bry. from Zanzibar," Proe. Zool. Soc. 1913, p. 477, pi. 58. 

 figs. 5, 6. 



This has a separable operculum (fig. 3), which seems to be general in 

 Cohered, but not in Scrupocellaria. The oral parts are thrown back as in 

 C. Darivinii, Busk, and the scutum comes up to the oral aperture, much as 

 in that species. The vibracular chambers are larger than is usual in 

 Scrupocellaria and spread diagonally halfway across the dorsal surface, but 

 they are not as large as is usual in Caberea. The seta of the vibraculum is 

 smooth as is general in Scrupocellaria *. It will be seen that this species has 

 some characters of Caberea, showing how closely that genus is allied to 

 Scrupocellaria. The seta is serrate, or, more strictl} r , spinous at one side 

 only, in C. grandis, Hincks, C. lata, Busk, C. rostrata, Busk, C. Ellisii, 

 Flem., C. Boryii, Aud., C. Hookeri, Busk, C. glabra, MacG., C. bursifera, 

 Ort., C. Darivinii, Busk, C. minima, Busk. The vibracular seta has several 

 irregular projections at the base, and at each side there is a separated curved 

 chitinous piece, against which the vibraculum evidently works. The central 

 vibracular muscles draw down the seta, and the sac-like " peculiar body " 

 naturally varies in position with the movements of the seta ; but, besides the 

 large t muscles, there is another muscle placed further away from the beak 

 (fig. 4, to.), attached to the flexible wall proximal to the seta, and thus the 

 chamber-wall is drawn in, reminding us of the way in which the front 

 membranous wall is drawn down in Micropora, Steganoporella, Cupularia, 

 and other genera. The lateral muscles are attached to projections on the 

 base of the vibracular seta (fig. 5). 



There is a small median avicularium placed near to the base of the 

 scutum. Miss Thornely refers to tall median avicularia. There is a chitinous 

 arch from the inner side of the area below the scutum. The ovicell is 

 imperforate, and there are 13 tentacles. 



Loc. Coast of Spain ; Adriatic; Lifu (Thosnely) ; Queensland {Haswell) ; 

 Zanzibar, 8 fath. (Waters) ; in the Indian Ocean (Providence, 50-78 fath., 

 Amirante, 29 fath., Farquhar reef, Cargados, 30 fath., Seychelles, 34 fath.) 



* In my paper on the Zanzibar Cheilostomata, Proc. Zool. Soc. 1913, p. 474, I unfor- 

 tunately stated that the vibracula of Caberea were smooth, which presumably was a slip in 

 transcribing. 



t With the circular movement of the seta it is questionable whether any of the muscles 

 should be called retractor or occlusor 



