420 Reviews — Etheridge and Carpenter — 



A penny Guide to the Geological Galleries appeared on their re- 

 opening to the public on 19 April, 1881, followed, by an illustrated 

 edition in 1882 (price threepence); a third followed in 1884; and 

 a fourth edition (price fourpence) in 1886. Of the three earlier 

 editions altogether 11,234 copies have been sold. A Guide to the 

 Fossil Fishes appeared in 1885 (price threepence). A Catalogue of 

 the Fossil Foraniinifera, by Prof. T. Eupert Jones, F.K.S. (8vo.), 

 appeared in 1882 (price 5s.). A Catalogue of the Fossil Sponges, 

 by Dr. G. J. Hinde, F.G.S., 4to. with 38 plates (price 30s.), in 1884. 

 A Catalogue of the Fossil Mammalia (8vo.), Part L, by Ei chard 

 Lydekker, B.A, F.G.S., was issued in 1885 (price 5s., with thirty- 

 three woodcuts) ; Part II. also in 1885 (price 6s., with thirty-nine 

 woodcuts); Part III. in 1886 (price 4s., with thirty woodcuts); 

 (Part IV. we are informed is now passing through the press). A 

 Catalogue of the Palasozoic Plants in the Geological Department, by 

 Mr. E. Kidston, F.G.S. (8vo. pp. 288, price 5s.), appeared in 1886. 



The present work was commenced by its authors some years since, 

 but their task was delayed by the necessity to collect materials which 

 might serve to illustrate in detail the minute structure of this curious 

 and extinct group of Echinodermata. They wei*e soon fortunate in 

 obtaining the co-operation of Mr. Charles Wachsmuth, of Burlington, 

 Iowa, a gentleman who has devoted some twenty-five years to the 

 collection of Crinoidea from the Carboniferous rocks of North 

 America, and who has also published several important memoirs on 

 these organisms. With his aid, and that of numerous other friends 

 in Europe and America, the authors have been enabled to examine 

 probably the largest and most instructive collection of these organisms 

 ever brought together, thus rendering the comprehension of their 

 minute anatomy comparatively easy, and giving one confidence in the 

 interpretation which they offer of each detail of their structure. 



With regard to the systematic position of the Blastoidea, one of 

 the authors (Dr. P. Herbert Carpenter) has had peculiar advantages 

 in approaching the subject, from his previous studies of the Crinoidea 

 collected by the " Challenger " expedition ; whilst both authors have 

 long and patiently studied the fossil forms, and have endeavoured 

 by the examination of numerous remains and by the preparation 

 of very many sections, exhibiting internal structure, accurately 

 to work out the morphology of this obscure and but little understood 

 group. 



The position of the Blastoidea in relation to the rest of the 

 Echinodermata has long been a subject of grave discussion ; but the 

 leading authorities are now agreed in giving the Blastoids a position 

 as a group equivalent in rank to the Brachiate Crinoids and the 

 Cystids, or to the Urchins and Starfishes. 



Blastoids with stems appear to be extremely rare, although there 

 is little doubt that the great majority were stalked forms. Indeed 

 the authors figure several examples (see plate iii. fig. 16 ; pi. v. 

 fig. 25 ; pi. vi. fig. 23 ; and pi. xvi. fig. 7) showing the remains of 

 stems. But the stem in Granatocrinus is of moderate size compared 

 to the diameter of the flat basal disc of which it occupies the centre. 



In Pentrernitidea, Oropliocrinus, Cryptoblastus, and Troostocrinus 



