1899] VERTEBRATE PALAEONTOLOGY 157 



centra " ; tins is possibly in deference to the views of Cope and Baur as to the 

 homologies of these elements, but in the reviewer's opinion both these writers 

 were mistaken, for if these parts are homologised at all with the elements of a 

 compound vertebra, they must be considered as pleurocentra, both because of 

 their paired structure, and of their relations to the neurapophyses and ribs. 



A similar inconsistency, which is perhaps even more serious, between the 

 earlier and later pages of the work, is seen in the use of the terms "scpiamosal " 

 and " supratemporal " ; all through the portions relating to the Teleostome fishes 

 and Stegocephalia, the dorsal anterior element immediately behind the post- 

 orbital is termed " squamosal," while the ventral or posterior element is termed 

 "supratemporal." In the latter part of the work these terms are reversed, and 

 the ventral posterior element in contact with the quadrate is properly termed 

 "squamosal" ; while the dorsal anterior element in the Theriodontia, Pythono- 

 morpha, and most subsequent sections is properly termed " supratemporal " or 

 " prosquamosal " (Fig. 9G, p. 153; Fig. 117, p. 192). As pointed out by Baur, 

 these bones were first named by Owen in this manner, and it is obvious that 

 the part nearest the quadrate should throughout be termed " squamosal," 

 because the term originated in mammalian anatomy, in which there is no 

 prosquamosal or supratemporal element. 



Another debateable use of terms, which concerns homology, is that upon 

 page 125, in the description of the dermal bones of the pectoral girdle of the 

 Stegocephalia, where mention is made only of an interclavicle and clavicles ; the 

 former being regarded by the highest authority, Gegenbaur, not as an inter- 

 clavicle at all, but as an episternum (that is, a part which, originates by the 

 union of dermal elements in the middle line of the chest, just as the para- 

 sternum or abdominal ribs originate in the region of the abdomen). There is 

 thus in the Stegocephalia an episternum, a clavicle and a supraclavicle (Seeley = 

 cleithrum, Gegenbaur), and this latter element, which the author fails to men- 

 tion, is of especial interest because it represents a vestige of the ancestral sus- 

 pension of the pectoral girdle from the skull, as observed in the Teleostomi. A 

 minor oversight is in the absence of definition of the term " amphistylic " (p. 

 33), while of more importance is the absence of definition, either in the text or 

 in footnotes, of the important ordinal and subordinal terms, such as " haplistia," 

 " actinistia," " rhipidistia," terms originally applied in full recognition of their 

 phylogenetic significance, and therefore worth fixing in the minds of students 

 by a brief reference to their meaning. 



The figures for the most part are extremely good, especially the original 

 synoptic series drawn from Amphibian and Reptilian skulls in the British 

 Museum. They are marred only by the abbreviations, which coincide with the 

 inconsistencies in the use of terms, above pointed out. The Mammalian figures 

 are the least satisfactory because the author has been obliged to borrow more 

 largely. On page 295 is inserted Marsh's restoration of Coryphodon, which is 

 to be regretted, because it gives an entirely wrong impression of the chief 

 characters of this animal. Here also we regret the use of the term Dinoceras, 

 which is pre-occupied by Uintatherilim. 



It is interesting to turn from these matters, which are of a more or less 

 technical character, to the discussion of the far more important treatment of the 

 relationships, phylogeny, and classification of the Vertebrata. Naturally in this 

 part of the work specialists find their greatest interest. 



The author, in the attitude of teacher, rightly takes a conservative position 

 upon most of the open phylogenetic problems. He clearly shows that he leans 

 towards the theory, that the closest relations of the Amphibia are with the 

 Crossopterygian fishes, and of the Mammalia with the Anomodont Reptiles. In 

 tracing the descent of the Mammalia proper, he adheres practically to the 

 theory of Huxley, namely, of the phyletic succession of Monotremes, Marsupials, 

 and of Placentals, the main objection to which is that no evidence can be 

 advanced in its favour. He accordingly regards the Mesozoic mammals, and 



H NAT. SC. VOL. XIV. NO. 84. 



