Reviews — R. Lijdehker — Fossil Mammalia. 425 



contour of the calyx is always perfectly symmetrical, consisting as 

 it does of five equal and similar radials, and five deltoids of the 

 same nature. 



The foregoing table (from p. 136) is extremely valuable as 

 showing the Distribution of the Genera of the Blastoidea in Space 

 and Time. We have added a column with the probable number 

 of species referred to each genus. 



From the foregoing list, it will be seen that only two (American) 

 generic forms, Troostocrinus and Codaster, occur in the Upper 

 Silurian, about six or seven genera in the Devonian ; whilst the great 

 majority occur in the Carboniferous series both in England and in 

 America. 



A careful description of each species is given by the authors, 

 illustrated by twenty quarto plates and 399 figures, most beautifully 

 and accurately drawn by Messrs. C. Berjeau and P. Highley, re- 

 quiring not only great artistic power, but a large store of patience 

 in making out such minute and very elaborate details. 



All Biologists who are interested in the Echinodermata must feel 

 grateful to the authors of this very elaborate and exhaustive Memoir, 

 which clears up so many points in the anatomy of this ancient class, 

 that has hitherto been but very imperfectly understood. 



We trust they may be so well satisfied at the favourable reception 

 which this volume is sure to meet with, that they will take up and 

 work out in the same earnest and painstaking manner the still more 

 important and interesting Brachiate division, which has remained 

 far too long neglected by palaeontologists. 



III. — Catalogue of the Fossil Mammalia in the British Museum 

 (Natural History), Cromwell Eoad, S.W. Part III. 1 Con- 

 taining THE ORDER UnGULATA, SUB-ORDERS PeRISSODACTYLA, 

 TOXODONTIA, CONDYLARTHRA AND AMBLYPODA. By R. LvDEKKER, 



B.A , F.G.S., etc. 8vo. pp. xvi. & 186. (London, 1886, printed 

 by Order of the Trustees.) 



THE present part of Mr. Lydekker's Catalogue of the Fossil Mam- 

 malia completes the order Ungulata with the exception of a 

 single group, the Proboscidea. This group, it is announced, will 

 form Part IV. of the Catalogue, which is now in the press. Although 

 embracing only a small section of the Mammalia, this part is of 

 special interest to the palaeontologist ; for out of the eighty species 

 recorded in its pages, all are extinct save four, namely, Tapirus 

 Americanus, Equus caballns, Bhinoceros sondaicus and Rh. unicornis. 

 Furthermore, of the seventy-eight extinct species, no fewer than 

 thirty-two species, belonging to as many as twelve genera, date back 

 to the Eocene Tertiary formation, namely, LopModon (5 species) ; 

 Hyracotherium (3 species) ; PacTiynoloplivs (4 species) ; JPalceotherium 

 (8 species) ; Anchilophus (2 species) ; Rhinoceros (2 species) ; Cadur- 

 coiherium (1 species); Periptyclius (1 species); Haploconus (1 species); 



1 Tart II. was noticed in the Geological Magazine, April, 1886, pp. 175-177. 



