ON FOSSIL POLTZOA. 139 



arrangement, triangular branches, and entire peristome are good features 

 in this species. 



The abundance of specimens of this species in the Garvel Park 

 deposits have enabled me to study the form in all its varying features. 

 It is a peculiarly Northern type, whereas the Idmonea radians, Lamarck, 

 its nearest ally, is as peculiarly Southern. The Fossil specimens from the 

 Garvel Park beds are, I have no doubt, closely related to, if not identical 

 with, the I. radians of Beneden ; and besides this, Mr. Busk and Mr. 

 Hincks give as synonyms, though doubtfully, I. coronopis, Def., and 

 I. mgustata, D'Orb.,as well. Mr. Waters (' Bay of Naples Bryozoa,' op. tit. 

 p. 269) remarks of the J. gracillima of'Reuss, ' that specimens in his 

 possession, from Val di Lonti, correspond with recent I. atlaniica. 



It is very possible that if the various specimens of this beautiful 

 species were isolated, or found in different localities even of the same age 

 as the Glacial deposits, they may be characterised as different species, 

 but mingling with such abundance in these beds, all the gradations of 

 variations may be traced, and it seems to me impossible to separate them. 

 With regard to the I. gracillima of Reuss from the Miocene beds of Val 

 di Lonti, and also from the Montecchio Maggiore beds of Northern Italy, 

 although specimens resemble, in some cases closely so, recent Idmonea 

 atlaniica, I should rather hesitate to put the one as a synonym of the 

 other. It may be possible to establish a connection between the 

 I. gracillima, Reuss (non Busk, ' Cyclostomata,' p. 14), and some of the 

 still undescribed Cretaceous species, and it may also be possible to show 

 gradations of type from J. gracillima to I. atlaniica. 



24. Idmonea serpens, Linnaeus = Tubipora ibid., Linn., ' Syst. Nat.' 



ed. 12, 1271. Tubulipora ibid., Flem., Couch, Johnst., Busk. 



Idmonea serpens, Van. Ben., Smitt (sub-genus), Hincks. (See 



for references, p. 453, 'Brit. Mar. Polyzoa,' vol. i. 1880.) 



This species, as a fossil, has a far more limited range than the above. 



I have specimens in the young state from the Glacial Beds of Scotland. 



A specimen, figured by Manzoni (' Bryozoa of Castrocaro,' p. 43, fig. 78, 



tav. vi.), Mr. Hincks accepts, on the authority— Pliocene, Castrocaro 



(Manzoni) ; Sicilian Pliocene (Waters). In his synonyms, Mr. Hincks 



also lvfers to this species — Tubulipora transversa, Lamk., and Idmonea 



ibid.. Milne-Edw. and D'Orb. In my own investigations I have not been 



able to place Idmonea serpens— type accepted by Hincks, Manzoni, and 



H aters — below the Pliocene beds. 



For fuller particulars, see Busk, ' Cvclostomata, Brit. Mus. Cat.' pi. 

 in. pp. 25-26 ; and Hincks, 'Brit. Mar. Poly.' {he. tit. p. 453). 



25. Idmonea teiquetra, Lamx. (author's) (' Jura formation,' Ranville). 



Brit, locality, Juras. rocks under London — Professor Judd's 

 material. 



Though not abundant, I have a few specimens of this species from 

 the material referred to by Professor Judd. The species is evidently 

 founded upon its peculiar triangular character rather than any special 

 features m the cells. After a careful study of the British specimens, the 

 following results have been obtained, which I give rather as a description 

 than as a diagnosis. I. Zoarium triangular, zoaicia arranged in lines — 

 sometimes flattened, some lines slightly produced ; the flattened cells are 

 Lepraha '-like, with a semicircular orifice, with the area punctured ; the 



