590 ZOOLOGY 



Chiroptera, not differing widely from existing forms, occurred 

 as early as the Eocene. 



Of the Primates, Prosimii occur from the Eocene onwards. 

 A single extinct family is known, comprising Lemuroids which 

 bear a closer resemblance to Insectivora than do the living 

 members of the order. Of the Anthropoidea, the Hapalidae and 

 Cebidae are only represented in the Miocene (Eocene ?) and 

 Pleistocene of South America ; the Cercopithecidae in the Miocene 

 and Pliocene of Europe and the Pliocene and Pleistocene of 

 India by extinct genera (Mesopiihecus, &c.) and by species of the 

 existing genera Macacus, Semnopithecus, and Cynocephalus, and 

 in the Pliocene of India, France, and Italy by species of extinct 

 genera. Among the Simiidse the Gibbons occur in the Miocene of 

 France, the Pliocene of Germany, and the Pleistocene of Borneo. 

 An extinct genus, Dryopiihecus, found in the Miocene of 

 Europe, is perhaps related to the Gorilla ; and a species of 

 Orang (Simia), together with a form allied to the Chimpanzee, 

 occurs in the Indian Pliocene. 



In deposits of late Pliocene or early Pleistocene age in Java have 

 been found the remains of an Anthropoid (Pithecanthropus) which 

 has been supposed to be an intermediate form between the man-like 

 Ap'es and Man. Traces of the existence of Man in the form of 

 flints of undoubted human manufacture have been found in the 

 Pliocene ; but any such evidences are extremely rare until we 

 reach the Pleistocene. 



THE MUTUAL ^RELATIONSHIPS OF THE CHORDATA. 



In discussing the relationships of the various groups of Chordata, 

 it will be convenient to begin with Fishes, and to work from them 

 upwards and downwards. 



The question of the inter-relationships of the various groups of 

 Fishes is a very puzzling one. As in other cases of the kind, there 

 are three lines of evidence to be kept in mind -'anatomical, 

 embryological, and palaeontological the last being always, when 

 available, the final court of appeal. 



With regard to anatomical evidence, it seems fairly obvious that 

 Fishes having neither limbs nor jaws are more primitive than 

 forms in which those structures are present, unless undoubted 

 evidence of degeneration can be produced ; that a purely 

 cartilaginous skeleton is more primitive than a bony one, and a 

 notochord than a vertebral column, however simple ; that a brain 

 with distinct cerebral hemispheres is more advanced than one 

 having an undivided prosencephalon ; that an autostylic skull, 

 being due to the concrescence of originally distinct parts, is more 

 specialised than a hyostylic skull ; that the loss of the spiracle 

 and the presence of an operculum and of a highly differentiated 



