PENNIRETIPORA. 189 



more oval, but probably our specimens might more resemble them if they were 

 not so cloaked by the matrix, which often almost or entirely covers the dissepi- 

 ments. F. multiporata, M'Coy, is united by Shrubsole with this species, and 

 there certainly seems nothing to distinguish it; the Pilton fossils seem midway 

 between them. 



Affinities. — F. quadridecimalis, M'Coy, 1 would appear to branch more rapidly, 

 and to have thinner branches and much more numerous pores. 



Whatever the specimens from Pilton referred by Phillips to his F. laxa may 

 be, their reticulation (as in the Carboniferous type) was very much larger than 

 that of the present species, e. g. in his figure (said to be natural size) it is more 

 than twice the length of that of our fossils, and the stems are wider than the 

 width of our stems and fenestrules together. It could not, therefore, be 

 reasonably regarded as the same species. 



II. Family — AcanthocladiiDjE, Zittel, 1880. 



1. Genus — Penniketipora, d'Orbigny, 1849. 



Goldfuss defined his genus Glauconeme 2 for four of Mimster's species belong- 

 ing to or in the style of Vincularia, and afterwards added a fifth species, G. disticha, 3 

 from the Bifel or from Dudley, to which his generic definition was not applicable. 

 The latter species, according to his figure, seems probably congeneric with G. 

 bipinnata, Phillips. In 1839 G. disticha was described from Dudley by Lonsdale* 

 in ' Siluria,' but in terms which imply that the Dudley fossil was more akin to 

 Ptilopora than to G. bipinnata, which Phillips in 1841 described from the Pilton 

 beds. In 1849 d'Orbigny 5 formed the genus Penniretipora, and defined it in 

 terms which, though slight, are consistent with the characters of the present 

 genus. He enumerated eight species, of which probably the first two do not 

 belong to the present genus, and the next four do. Curiously enough he omits 

 G. bipinnata, and places it under M'Coy' s genus IcJdhyorachis, having possibly 

 mistaken Phillips's drawing of the reverse side for the obverse. In 1884 Vine 6 

 formed a new genus, Pinnatopora, with G. bipinnata for its type, and restricted 

 Glauconeme to G. disticha, Lonsdale. In 1890 Ulrich 7 followed Vine as to 



1 18-14, M'Coy, ' Synopsis Carb. Foss. Irel.,' p. 204, pi. xxviii, fig. 13. 



2 1830, Goldfuss, ' Petref. Grerni.,' vol. i, p. 100, and p. 101, note on Vincularia. 



3 Ibid., p. 217, pi. lxiv, fig. 15. 



i 1839, Murchison, ' Sil. Syst.,' p. 677, pi. xv, figs. 12— 12 d. 



5 1849, d'Orbigny, 'Prodrome,' vol. i, p. 45. 



6 1884, Vine, ' Eeport Brit. Assoc.,' 1883 (Southport), pp. 191 and 192 (woodcut). 



7 1890, Ulricb, ' Geol. Surv. Illinois,' vol. viii, p. 614. 



