BKYOZOA OF THE CAPE VERDE ISLANDS. 15 



Orossland sent some thick pieces from underneath a coal-lighter, in St. 

 Vincent Harbour, Cape Verde Islands, and says, "this is the first of the host 

 of forms to make an attachment to the lighter." One block was about 

 170 mm. x 140 mm. and 7 mm. thick. Some colonies occur on a stone 

 brought up by a diver. In my last two papers * it has been pointed out that 

 the zooecia are frequently superimposed, and this I referred to in a species 

 of Meliceritites. Reuss has shown the same thing in Cumulipora aiu/ulata, 

 v. Maehr, and Lee f calls attention to Ulrich +, saying, " in the Trepostomata 

 and many Cryptostomata the tubular zooecium really represents a series of 

 superimposed cells." 



This species shows the " closures " more clearly and distinctly than any 

 other I have come across. The calcareous matter is evidently deposited by 

 a cellular tissue over the operculum. When a zoarium consisting of several 

 layers is examined from below, the chitinous opercula in the older layers 

 may nearly all be seen remaining in the oral aperture in their natural position, 

 and when the zooecia from these lower layers are examined from above the 

 opercula are mostly without any calcareous growth, while others have a 

 calcareous layer over part or all of the operculum. Near the centre of the 

 operculum, or rather distal to the centre, a tubule grows through this super- 

 opercular deposit, which may be quite short (rigs. 14, a, b) or may form a 

 noticeable tube, for in one case a fine tubule joins the inner wall of the next 

 layer of zooecia (fig. 14, d). The mandibles in S. spongites, Smitt, are also 

 sometimes similarly covered with a calcareous deposit. 



ScMzoporella viridis, Thornely, in large masses, shows in the upper layers 

 no calcareous deposit on the opercula, nor any tubule or tubercle ; but when 

 the upper layer is scraped away, then the opercula of the underlying zooecia 

 are mostly seen to have a stout tubercle over the middle, but only in a few- 

 cases is there any calcareous deposit. The new zooecia in S. viridis are 

 placed irregularly, quite independently of the layer below, and only 

 accidentally do the walls of the new zooecia pass over the old opercula, but 

 where this has occurred there is in one or two cases a thickening of the 

 operculum under the new wall. We thus see that the position of the layers 

 of zooecia is quite different in S. viridis (fig. 18) to what occurs either in 

 S. unicornis or in S. porelliformis §, nov. (PI. 2. figs. 19-21, an African 



* " Bry. Sudanese Red Sea," Journ. Linn. Soc, Zool. xxxi. (1909) p. 144 ; " Bry. from 

 Zanzibar," Proc. Zool. Soc. 1913, p. 502. 



f " Brit. Carb. Trepostomata,'' Mem. Geol. Surv. of Great Brit., Paleont. vol. i. pt. 3, 

 p. 145 (1912). 



X Ulrich, E. 0., "Pal. Bry.," Pal. of Illinois, Geol. Survey Illinois, vol. viii. pt. 2, p. 322 

 (1890). 



§ Schizoporella porelliformis, sp. nov. (PL 2. figs. 19-21). It is much like S. nivea in 

 most characters, but is larger with larger aperture, &c. The surface and the large round 

 ovicells have large pitted pores. It is bi-multilamiuate. The oral aperture is nearly 

 round, as the sinus is nearly the width of the aperture. The operculum has the muscular 

 attachments at the side, and not from bosses distant from the border. There are one or two 

 small oval avicularia at each side of the aperture. 



