60 VERTEBRATE ANCESTORS OF MAN ? 



races took place. This Anthropolithic time com- 

 prised the Glacial, Post-Glacial, and Historic periods. 



Under the head of Ontogenesis, I have anticipated 

 all that need be said relating to the Invertebrate 

 stages of the alleged phylogenesis of man ; I shall, 

 therefore here take up the line with the Vertebrate 

 stages, and then conclude with a retrospective 

 summary of the whole. 



The series of man's vertebrate ancestors begins, 

 according to Haeckel, with a hypothetical animal 

 which lived during the primordial time, and of the 

 characters of which we have presented to us a dis- 

 tant idea in the still living amphioxus or lancclct. 



The lancelet tribe just mentioned forms Haeckel's 

 ninth stage in the phylogenesis of man. His tenth 

 stage comprises cyclostomatous fishes, or fishes of the 

 lamprey tribe, which he names Monorrhina or single- 

 nosed, as they have only one nasal cavity — a 

 character in which they differ from true fishes. 



The eleventh ancestral stage of man was repre- 

 sented by proto-fishes. These, Haeckel considers, 

 were evolved from monorrhina by the division of the 

 single nostril into two lateral cavities, and by the 

 acquisition of branchial arches and a jaw skeleton, — 

 of a swimming bladder and two pairs of limbs in the 

 shape of pectoral and abdominal fins — besides other 

 characters. These proto-fishes, Haeckel thinks, 

 resembled the lowest squall (or fishes of the shark 

 tribe) of the present day, and already lived in the 



