ALG.'E. 



H9: 



pores, corresponding with the lateral whorled processes, may very 

 readily be mistaken for the tubes of polypes or the chambers of 

 polythalamous Foraminifera ; and the fossil forms of the family were 

 until recently regarded as referable to the animal kingdom. It was 

 first shown by Munier-Chalmas (" Comptes rendus," torn, lxxxv. 

 p. 814, 1877) that the supposed Foraminifera described under the 

 names of Dactylopora and Ovulites were really referable to the Algce, 

 and that, along with many other types, they belonged to the group 

 of the Siphonece verticillatce. Palaeontologists, in fact, are now 

 acquainted with an extensive series of fossil forms of this remark- 

 able family of Algce, which not uncommonly give rise to very con- 

 siderable rock-masses, and thus become of geological importance. 

 The oldest type of the Siphonece verticillatce is apparently the Ccelo- 

 trochium of the Middle Devonian of the Eifel ; though the nature 

 of this fossil is not absolutely certain. The Carboniferous Limestone 

 of England also sometimes contains numbers of small calcareous 

 cylinders, with a porous surface, which are probably referable to this 

 family ; but further investigation is needed before this can be posi- 

 tively asserted. It is, also, not impossible that the organism de- 

 scribed by De Koninck from the Carboniferous Limestone of Bel- 

 gium, under the name of Monticulipora inflata — which likewise 

 occurs in the same formation in Britain, and sometimes attains a 

 considerable size — may really be a peculiar type of the Siphonece. 

 Apart from the above, the first undoubted appearance of forms of 

 this family is in the Permian rocks, in which the genus Gyroporella 

 is found. It is, however, in the Upper Trias that the maximum 

 development of the Siphonece verticillatce takes place, the limestones 

 of this period being often essentially made up of the cylinders of 

 Gyroporella and Diplopora, as occurs, for example, in the Bavarian 

 and Tyrolese Alps. Various forms of the group also occur in the 

 Jurassic and Cretaceous rocks, while there are numerous Tertiary 

 types : but the family is at the present day represented by but a few 

 species, and the range of these is very limited. 



Among the more important types of the Sipho?iece verticillatce 

 which occur in the fossil state are species belonging to the genera 

 Cymopolia, Larvaria, Dactylopora, Gyroporella (with Diplopora), 

 and Uteria. In Cyvwpolia (fig. 1360) the thallus is branched, and 

 is covered with a hollow calcareous crust, the surface of which shows 

 close-set pores. The lateral processes, sterile and fertile, are devel- 

 oped in whorls, separated by vacant nodes. A living species of this 

 genus is found in the seas of the Canary Islands and West Indies ; 

 while the calcareous cylinders of fossil forms occur not uncommonly 

 in the Eocene Tertiary, and were originally described under the name 

 of Dactylopora. The genus Larvaria is nearly allied to Cymopolia, 

 and likewise includes forms — such as L. ernca (fig. 1361, a) and 



