﻿Revieics — The Palceontographical Society. 227 



known in the Mediterranean ; but in none of these three deposits does there occur 

 a single species of the converse character. 



" Simultaneously with these features, we find a proportional increase of 



the Arctic species as we ascend through the Crag and Glacial series ; and that even 

 in the Post-Glacial deposits no less than four out of a total of forty-nine are Arctic 

 shells of the preceding Glacial Period, which have since receded from the British 

 coasts. 



"The Middle Glacial fauna stands out in some discord with the above; since in it 

 not only do several Mediterranean species unknown to British seas reappear, but the 

 proportion which these bear to the number of British species not known in the Medi- 

 terranean is as eight to twenty-one, — a much larger proportion than exists in the 

 Fluvio-marine Crag, and altogether beyond the proportions exhibited by the inter- 

 vening formations. The explanation is probably to be found in the MoUuscan 

 remains of this deposit having travelled from some distance, as mentioned in the Intro- 

 duction to this Supplement, p. xxiii. Altogether this Middle Glacial assemblage is a 

 very interesting one, and the most important of any of the formations succeeding the 

 Crag. Several of the species which occur in it seem to have disappeared from 

 the iBritish coast during the earlier part of the Red Crag ; and while some of these 

 are not known living, others are confined to the Mediterranean or otber southern 

 waters. 



" I have only to add that I am equally convinced with the authors of the Intro- 

 duction to this work, that the Molluscan remains of the Middle Glacial Sand 

 (fragmentary and worn as they occur in it) are not derived from any older deposit, but 

 are contemporaneous with the sand which contains them." 



4. To osteologists, and those who study the fossil dragons of the 

 Wealden and Purbeck formations, the continued labours of the inde- 

 fatigable Professor Owen bring grand results in the descriptions and 

 figures of remains of Igiianodon Mantelli, I. Hoggii (?), J. Foxii, 

 J/ylcBochampsa Vectiana. In the same volume the author continues 

 his researches on the Mesozoic Fterosauria, describing and illus- 

 trating many relics of Pterodactyles from the Gault, Hastings Beds, 

 Kimmeridge Clay, Great Oolite, and the Lias. 



2, — Monographs of British Fossils. Published by the Palason- 

 tographical Society. Vol. XX VIII. (for 1874). 4to. (London, 

 1874.) 

 I. This volume has. fewer Monographs, or parts, than usual ; but 

 one, and that fortunately a complete work, is bulky in text and 

 enriched with sixteen plates, which have an average of upwards of 

 SO figures in each ! These (all drawn by G.. S. Brady, and litho- 

 graphed by T. West and G. West) illustrate the minute Bivalved 

 Entomostraca which occur plentifully in many clays and loams of 

 Post-Tertiary date, and have their analogues, and often their exact 

 representatives, in the existing seas, lakes, and rivers. The Palaeon- 

 tographical Society has already published Monographs by Rupert 

 Jones on the Cretaceous and Tertiary species ; and the present Mono- 

 graph, by Dr. G. S. Brady, a first-rate carcinologist, with whom the 

 Entomostraca are favoured pets, aided by two careful naturalists 

 and geologists, Messrs. H. W. Crosskey, F.G.S., and D. Eobertson, 

 E.G.S., advances our knowledge of these small, but true and useful 

 witnesses of past conditions, bringing them en rapport both with 

 those that are found fossil in older deposits and those now living. 

 The classification of the Ostracoda (the special group of Bivalved 

 Entomostraca treated of in this Monograph), according to the shape, 



