SPECIES OF CLADOPHOEA. 



173 



in the manner of those of Dicellograptus, Hopk. ; and the line 

 of the aperture lies wholly within the ventral margin of the 

 branch. 



Horizon and Locality. Llandovery of Devil's Bridge, Aberyst- 

 wyth, Cardiganshire. Collection of Dr. Huinpidge, Aberystwyth. 



Genus Calyptogeaptes. 



Calyptograptns, Spencer, Canadian Naturalist/ 1878-79, p. 459. 



" Gen. char. Polypary cyathiform, with numerous bifurcating 

 branches, which are dichotomous at the termination, but are not 

 connected by lateral processes. The branches are marked with 

 striae resembling rhomboidal pits ; the axis has a black corneous 

 exterior ; and the radicle is composed of a thickened mass of the 

 same texture as the branches. In appearance and texture this genus 

 resembles Dictyonema ; but the branches are all independent, not 

 being connected by transverse dissepiments as in that genus, and are 

 only united in one mass at the root " (Spencer, he. cit). 



One of the Cladophora collected by Professor Keeping appears to 

 possess many of the foregoing characters, which are given by Mr. 

 Spencer as the peculiarities of his genus Galyptograptus. There are, 

 however, some marked distinctions between our species and his 

 typical examples ; nevertheless it is most undoubtedly a closel}- 

 allied form, and may therefore most conveniently be provisionally 

 placed in this genus until we know more of the proper generic 

 distinctions of these obscure fossils. 



4. Calyptogeaptes ? plemoses, sp. nov. Plate VII. fig. 4. 



Polypary cyathiform '?, in the growing state, about one inch and 

 a half in height, composed of numerous bifurcating polypiferous 

 branches united into a short stem, longitudinally striated, not 

 connected by transverse dissepiments. Calycles closely arranged, 

 biserial. Basal disk elliptical in form, about one fourth of an inch 

 in diameter. 



The stem, which is very short and stout, rises from the centre of 

 the basal disk, and divides for the first time within about one eighth 

 of an inch of its origin ; the second, third, and fourth subdivisions 

 are about one tenth of an inch apart ; the later bifurcations are a 

 little more remote. The primal branches are about one thirtieth 

 of an inch in diameter ; the final branchlets are almost capillary. 



The substance of the polypary appears to have been somewhat 

 membranous in character, and is wrinkled or striated longitudinally 

 in the fossil. Two series of calycles are just discernible in the 

 proximal portions of some of the branches, their apertural margins 

 being Exhibited as short slits crossing the branches transversely, 

 almost at right angles to their general direction. 



This form agrees with Dictyonema and Callograptus in the regular 

 dichotomous nature of the method of subdivision of its principal 

 branches. It differs, however, most markedly from both these 

 genera in the apparent absence of the transverse dissepiments 



