Reviews — Fourtau's Egyptian Echinoids. 315 



required position to be achieved. In yet other cases where even that 

 expedient would have failed, a skeleton explanation printed at the top 

 of the facing page, to be followed by the detailed explanation, would 

 have been of great assistance. 



Anything which lessens chances of misquotation and facilitates 

 reference to a work makes that work, in our opinion, the more 

 valuable. And frequent reference to such a work as this is to be 

 desired, for the monograph thoroughly deserves it. We congratulate 

 Dr. Walcott on the completion of a magnificent task, most worthily 

 executed. It is another monument to his great abilities. 



III. — Catalogue des Invertebkes fossiles de l'Egtpte eepeesentes 

 DANS LES Collections dtj Gteological Museum au Caike. Par 

 E,. FouKTAU. Terrains tertiaires. lere partie : Echinides Eocenes. 

 4to ; pp. 1-93, pis. i-vi. Le Caire. Gouvernement egyptien. 

 Administration des Arpentages. 1913. 



DURING the Cretaceous and Eocene periods the Echinoid fauna of 

 the Mediterranean region seems to have been one of the richest 

 known from any part of the world. In the case of the former period 

 the wealth of species and individuals may probably be ascribed to the 

 littoral conditions then prevalent in Northern Africa, where, perhaps 

 in a tropical climate, shore-life must have been uniformly prolific. 

 It might be expected that the relatively pelagic conditions which 

 came in with the Tertiary epoch would have resulted in a reduction 

 in numbers and variety ; and, indeed, it may yet be a question 

 whether the list of 130 species recorded from the Egyptian Eocene 

 alone may not in some measure owe its length to excessive zeal in 

 the separation of ' species '. This question seems the more appropriate 

 when it is found that the genus Sehizaster is credited with eighteen 

 species and Schinolampas with nineteen ! 



In the study of the fossil Echinoids of the eastern part of the 

 Mediterranean the mantle of de Loriol has fallen upon M. R. Fourtau, 

 and he proves himself a worthy successor in the task of analysing 

 the, as yet, fragmentary knowledge of the fauna. The present 

 catalogue supplies a valuable resume of past work on Egyptian Eocene 

 Echinoids, and adds not a few new forms to the list. 



Although the main work is necessarily purely systematic, the 

 aiithor gives an interesting ' apologia ' in his Introduction. The 

 methods of systematists often seem to date from the earlier half of 

 last century, when, in the absence of any definite creed of evolution, 

 the slightest differences between two specimens must needs lead to 

 their specific separation. Although M. Fourtau adopts these methods 

 in no small degree, he gives at the outset a confession of faith in the 

 principles of the " Enchainements du monde animal ", He anticipates 

 that, with fuller knowledge, it will be possible to unite many of the 

 * species ' described in his catalogue into genetic series, but he regards 

 all such attempts at present as being premature. He differentiates 

 very properly between the zoological and stratigraphical conceptions 

 of species, and reluctantly restricts his palaeontology to its geological 

 aspect. 



