Notices of Memoirs — G. R. Vine on Fossil Polyzoa. 475 



This genus Is very fairly representee! by specimens in the Museum 

 Pract. Geol. There are no fewer than ten species named, and three 

 marked " New Sp.," awaiting description. Accepting the work of 

 other authors, I can do no more than furnish notes on them, just as 

 they are named. The first specimen is P. dichotowa, Portlock, in 

 the Wyatt-Edgell Colh, and is found in the Lower Llandeilo flags, 

 and the species ranges into the Upper Llandeilo and Caradoc. In 

 the Caradoc, also, we have the P. acuta, Hall, which, if correctly 

 identified, is very widely distributed in the American and Eiiglish 

 Silurians of the same horizon ; and P. explanata, M'Coy. Three 

 species undescribed, but bearing MS. names by Mr. Etheridge : P. 

 papiJlata, P. ramosa, P. scutata. In the Lower Llandovery we have 

 the P. fucoides, M'Coy, a species having a very limited range. In 

 the Upper Llandovery we have P. hinceolata, Lonsd., which ranges 

 through the Wenlock Shale, Wenlock Limestone, Lower Ludlow 

 and Aymestry Limestone. There is a departure from the type in P. 

 scaJpelhim (Eschara ? scalpelhim, Lonsd.) ; it is marked as appearing 

 in the Upper Llandovery and Wenlock Limestone. Hall, in the 

 filrst vol. of the Pal. New York, figures and describes P. (Sticto- 

 pora) acuta, which he compares with this species of Lonsdale. In 

 this species, too, there seems to be no central laminar axis. It is 

 found in the Trenton Limestone. With regard to Piilodictya lanceo- 

 lata, Lonsd., and PL lanceolata, Goldfuss, there seems to be a little 

 confusion in our varied identifications of species. In the Catalogue 

 of Cambrian and Silurian Fossils,' all the P. lanceolata found in the 

 Upper Llandovery to the Upper Ludlow series, with the exception 

 of one species found in the Wenlock Limestone, are ascribed to 

 Lonsdale. The Wenlock species is identified as that of P. lanceolata, 

 Goldfuss. This confusion is to be regretted, and in justifying the 

 course taken by Mr. E. T. Newton in the Catalogue, I would suggest 

 that the Wenlock shale species receive a new name — P. Lonsdalii. 

 There are many characters in this species distinct from the species 

 described by Goldfuss as Fhistra lanceolata. There is also a pressing 

 necessity that the types of Ptilodictya should become fixed, either as 

 a genus or as a family. 



Ptilodictya scalpelhim is a type somewhat different from that of 

 other species, and under a family name — Ptilodictid^ — I should 

 reconsider my own reference to this genus of the Carboniferous 

 Sulcoretepora.''' 



Professor Nicholson " has added much to our knowledge of this 

 group, hy the publication in this country of his papers on American 

 forms. He has also founded two new genera to take in what he 

 considers to be allied types. The Upper Silurian species, which 

 are new, are: 1. P. falciformis, Nich., allied to Esrharopora recta, 

 Hall. His species, however, differs from Flustra (Ptilodictya) 

 lanceolata, Goldf., P. gladiola and P. sulcata, Billings. 2. P. 

 emacerata, Nich., a beautifully delicate species, with " elliptical cells, 



1 Mus. of Practical Geology, 1878. 



^ Carboniferous Polyzoa, B. A. Pep. 1880, secoud page of Peport. 



3 Ann. Mag. iS'at. Hist. March, 1875. 



