Revieus — Dr. Davichon's Bnichiojjoda. 429 



Above are given all tlie characters of which the specimen presents 

 anjr reasonable suggestion. I have ventured to put an interpreta- 

 tion upon some of the characters for which the evidence is slight, in 

 the hope that those possessing specimens of any kindred forms may 

 throw light upon this one by confirming the interpretation here 

 given or suggesting a better one. 

 Dimensions : — 



Total length 10 centimetres. 



Greatest width 5-7 



Length of telson (about) 4*0 



Length of buckler (about) 2*0 



Greatest thickness of telson 0'7 



Horizon. — Chemung Group, Upper Devonian ; the " third oil 

 sand " of I. C. White, 2nd Pa. Survey. 



Locality. — Le Boeuf, Erie County, Pennsylvania. 

 The original specimen is among the collections of the U.S. Geolo- 

 gical Survey, and will be deposited ultimately in the National 

 Museum. 



Comments. — This specimen throws back the known range of Prest- 

 wichia, or at least the type to which this genus belongs, to an earlier 

 stage than heretofore reported. The earliest previously known 

 Frestwichia occurs in the Carboniferous. 



If my interpretation of its characters be correct, Prestioichia bears 

 closer relations to Limulus than is suggested by other known speci- 

 mens, and also it possesses features linking it with Trilobites and 

 Eurypterids. 



[The author illustrates his paper by a photo-engraving from a 

 drawing, of P. Eriensis, of the natural size, and two diagrammatic 

 figures of the supposed upper and under surface. The specimen, 

 although of great interest, is too obscure to permit us to draw any 

 positive conclusions from it, save the fact of the important discovery 

 of a Limuloid Crustacean in rocks of Devonian age in Pennsylvania. 

 A still earlier Limuloid form has, however, been met with in the 

 Upper Silurian of Lesmahagow, Lanarkshire, and described by the 

 writer under the name of Neolimulus falcatus, H. W., see Geol. 

 Mag. 1868, Vol. Y. pp. 1-3, Plate L Fig. 1.— H. W.] 



la E ^V I IE AAT" S. 



The Pal^eontographical Society. A Monograph of British 

 Fossil Brachiopoda.^ By Thos. Davidson, LL.D., F.R.S. 



WITH the present appendix (vol. v. part iii.) a monumental work 

 has been brought to a close.^ The labours of Thomas Davidson, 

 LL.D., F.R.S., need no introduction to Paleontologists of any part 

 of the world. The quiet distribution of the concluding fasciculi 

 of the " British fossil Brachiopoda " should not be allowed to pass 

 without notice. 



1 Science, vol. v. p. 409, 1885. 



2 Thnre is, we understand, a Bibliographj' of the Brachiopoda ready for issue in 

 the volume tor 1885, by Dr. Davidson, which equals the work iu its proportions and 

 exhaustiveness. 



