U .Mr. A. \V. Waters on 



The 0(rciostome,tlu)ugli not toucliing. is near to tlic zooccium, 

 and is wiile witli only a short tnhe, and in the specimen 

 (tig. 8) tlie ovicell tnrns over ou the dorsal surface on hoth 

 sides, the houndary being seen as a small arc at the back. 



It occurs frequently on the Poshlonia thrown upon the 

 Mediterranean coast, as well as on other sca-wceds. It agrees 

 very closelv with /. vxeneylimii, II., and perhaps should be 

 so named — the latter occurs at much greater depths and is 

 free and erect. 



For special reasons serpens will be considered more fully 

 when Tabniipora is dealt with, as T. serpens seems to have 

 been used as the name for at least four species, and it is 

 only provisionally mentioned now; subsequently it is hoped 

 to bring T. serpens out of its present muddle. 



The primary disk of /. serpens measures about 0'16 ram. 

 across, and there seems to be an approximate relationship 

 between the size of the disk and the size of the zooccia, the 

 first being the wider. The size of the di^k of T. lUiacea, 

 llarmer, is about O'l mm. ; T. dilatans, John., 009-01 mm. ; 

 T. lamourouxii., Aud., 12 mm. ; T. jmlchra, MacG., 

 0"12 mm. ; T. ventricosa, B., 028 mm. ; T. plumosay Th., 

 0'28 mm.; T. incrassaia, Sm., 015 mm.; Lichenopora 

 radiata, And., 0"11 mm.; Diastopora, 0*1 mm. 



Loc. Naples, Rapallo, Mentone, San Remo, St. Raphael. 



Idmonea philippsee, Harraer. (PI. II. fig. 6.) 



Iteptotul/i(/era philippsfc, Ilarmer," I'olvzoa of the 'Siboga' Expedition," 

 Ento. Ctenost. & Cyclos. pt. i. p. 120, pi. x. iiix. 9 (I'Jlo). 



Platonea philippsee, Cauu & Bassler, North Auiericau Early Tert. 

 Bry, p. 750, fig. 248 (1920). 



From the Mentone laminarian zone, ou Posidonia thrown 

 up on the coast, I fouud a specimen which certainly secrus 

 to be this species. It was longer than the part figured, 

 the zocEcia show considerable irregularity in numljer being 

 usually three in a series, but sometimes three or four, with 

 most irregularity neitr the ovicell. It has much in common 

 with /. serpens, and it looks as though it might have arisen 

 from being obliged to grow upon very narrow stalks or the 

 broken strips of Posidonia leaves. 



In 1. serpens and other creeping forms there is in places 

 an attachment-layer, often thrown out for a short distance, 

 and it may happen to grow similarly ou each side of the 

 zoarium (fig. 3). This is what Gregory calls a wing-like 

 selvage in his Idmonea alipes"^, and which Ilarmer (luc. cit.) 



* Cat. B.M. Cretaceous Brvozoa, vol. i. p. lo2. ])1. viii. figs. 2, .'}, 4 

 (18!»9). 



