A RETROSPECT. vii 



* Synopsis of Fossil Ecbinoderms of the Swiss Alps,' in which numerous species from the 

 Nummulitic formation are found figured. He has given also indications of certain Alpine 

 species in his ' Protozoa Helvetica' (37). I have described also some Echinides from the 

 Neocomian of Mont Saleve (39), from the Valangian of Arzier (40), and the Urgonian 

 of Landeron (41). I have also undertaken, under the title of ' Echinologie Helvetique ' 

 (42), the publication of the Fossil Urchins of Switzerland. In the First Part compre- 

 hending the Jurassic Echinides I had the happiness of having for my collaborator 

 M. Desor. I afterwards finished alone the Second and Third Parts, which treat 

 of the Cretaceous and Tertiary Echinides. Four hundred and thirty-eight species 

 •are the contingent of the Echinitic fauna furnished up to the present time by the Secondary 

 and Tertiary formations of Switzerland. 



Thanks to M. Cotteau, the Fossil Echinides of Belgium, hitherto known in a very 

 summary manner, have been submitted to a new and very necessary revision. He has 

 published, in succession, a ' Note on the Cretaceous Echinides of Hainaut ' (43), with some 

 species figured ; the ' Description of the Echinides of the Calcaire Grossier ' of Mons, 

 Senonian (44) ; and the * Description of the Tertiary Echinides of Belgium ' (45), an 

 important Monograph, in which thirty-one species are found figured and described, and of 

 which thirteen species only were previously known, and the most of these very imperfectly. 



It is likewise to M. Cotteau that we owe the knowledge of three interesting species 

 from the Upper Chalk of Sweden (46). 



Among the works which have appeared on the Echinides of Germany it behoves me 

 to cite, in the first place, the volume on the ' History of Fossils of Germany,' which 

 Professor Quenstedt has devoted to the Echinides (47). The Atlas of twenty-eight 

 plates contains no less than 1700 figures, with numerous magnified views; whilst the 

 text treats of not only the Echinides of Germany, but also many others which are 

 not found there. This work, the result of very considerable labour, comprehends 

 a great number of useful indications and previous observations ; but it is to be regretted 

 that Professor Quenstedt persists in his refusal to accept the nomenclature adopted in 

 the mean time by all authors and corresponding to the actual state of our knowledge. 

 The want of method and the improper denominations occasion much confusion, so that 

 the practical utility of the work is much diminished. " Die Echiniden '' has, nevertheless, 

 a real value, and has advanced science principally in making known several details of the 

 structure of many species which had not been previously observed, and in many cases it 

 will be consulted with advantage. The Chalk of the North of Germany has furnished to 

 M. Schliiter (48) many new species which he has described and figured. Subsequently 

 he indicated some others, but only gave short diagnoses of them (49). Besides, 

 many of the Cretaceous species from the same region have been well figured and 

 described by Schlcenbach (50) ; and M. Dames has given a description of the Jurassic 

 species collected in the North-west of Germany. The Echinides of the Upper Creta- 

 ceous strata of the Valley of the Elbe have been described and figured by Prof. 



