378 Reviews — R. Lydehher''s Catalogue of Fossil Birds. 



are intercalary cartilages ; there are seven branchial arches ; the 

 shoiilder-girdle is comparable to a branchial arch ; the paired fins 

 must have developed from a series of parallel rays, and the joints of 

 the axial rod have arisen partly by thickening, partly by the fusion 

 of several adjoining rays ; there are no pelvic elements, the so-called 

 "pelvis" being the basipterygium ; the claspers of old males are 

 similar to those of existing Sharks, and there are also the same 

 developments in aged females ; the oval eggs have a strong capsule. 

 In conclusion. Dr. Fritsch finds the nearest living allies of the 

 Pleuracanth fishes in the remarkable family of Notidanidse, and 

 adds the inevitable " Stammbaum " to show the ancestral position in 

 w^hich he would place them. Few who closely study the evidence 

 will fail to be convinced of the reasonableness of this arrangement ; 

 and the majority will doubtless be disposed to follow the Professor 

 in his most interesting theoretical excursus on the origin and 

 development of the paired fins. Recent discoveries compel us to 

 add only one word of caution, namely, that it is rash to assume 

 there were no groups higher than the so-called "Urfische" retaining 

 the primitive parallel disposition of the cartilaginous rays in the 

 paired fins. The fishes with a Cladodont dentition lately made 

 known by Dr. Newberry from the Lower Carboniferous of Ohio 

 iTnder the names of Cladodus Kepleri and C. Fyleri, seem to have 

 been true Elasmobranchs ; but their pectoral fins are not "archi- 

 pterygial " in the sense of Gegenbaur's terminology, and appear to 

 consist merely of segmented parallel bars. However this may be, 

 the recent rapid advances in our knowledge of the palseontology of 

 the Palasozoic Elasmobranchs must be a source of much gratification 

 to all who are interested in the evolution of the vertebrata ; and to 

 no one are we indebted more than to Dr. Anton Fritsch for enduring 

 contributions to the subject. A. S. W. 



II. — Catalogue of the Fossil Birds in the British Museum 

 (Natural History), Cromwell Eoad, S.W. By Eichard 

 Lydekker, B.A., F.Z.S., F.G.S. (London, 1891.) Printed by 

 order of the Trustees, and sold by Kegan Paul, Trench, 

 Triibner & Co. 8vo. pp. i-xxviii, and 368, with 75 Woodcuts. 



MR. LYDEKKER has earned the hearty thanks of all those 

 who are interested in the palseontological history of the 

 higher Vertebrates, by the valuable series of Catalogues of the Fossil 

 Mammalia, Aves, Reptilia, and Amphibia which he has prepared, 

 under the auspices of the Trustees of the British Museum (Natural 

 History), which form ten separate parts or volumes, containing 3119 

 pages of text illustrated by 537 woodcuts. The earlier published 

 volumes have already been noticed in this Magazine, and we now 

 liave much pleasure in drawing attention to the final volume on the 

 Fossil Birds, which has just been completed. If we except the 

 Amphibia, the class Aves forms the smallest group of Vertebrates 

 known in a fossil state ; yet the number of living species exceeds 

 8000. Thirty-five years ago, it appeared as if the hope of 



