RECENT PROGRESS IN BIOLOGY. 665 



essential respects. Thus the facts with regard to the growth of birds 

 from the egg are, in regard to large features, the same which have 

 been carefully ascertained with regard to the common fowl. The 

 growth from the egg of ordinary hairy quadrupeds presents the same 

 characters as that of the rabbit, the dog, and man. The history of 

 the changes of the eggs of fish on their way from simple homogeneity 

 to the rich complexity of adult life is practically the same for all fish 

 truly so called ; and so we may say of insects that one insect fur- 

 nishes the history which is true of all. This, be it remembered, re- 

 lates only to large and general features. But naturalists are acquainted 

 with a number of strangely abnormal animals which will not enter into 

 large groups and even defy classification, being neither " flesh, fowl, 

 nor good red herring." These recalcitrant animals are not objection- 

 able to the zoologist ; on the contrary, they are his favorites. It is 

 these which he is most eager to study, and it is from them that he ex- 

 pects to obtain information which will clear up doubtful points in the 

 scheme of relationships or pedigree which he has provisionally con- 

 structed on the basis of his acquaintance with less isolated forms. 

 These exceptional forms of animal life are found in various parts of 

 the world, and are often difficult of access. Nevertheless, if the nat- 

 uralist is to study the growth from the egg of these animals, he must 

 follow them to their native homes. Botanists have a great advantage 

 over zoologists in the fact that most plants are readily transported 

 from one locality to another, and can be cultivated in artificial climates 

 produced in glass houses. We have at present no such skill in the 

 treatment of animals, and accordingly the energetic Cambridge natu- 

 ralists have risen to the necessities of the case. Within the last three 

 years special journeys have been undertaken from Cambridge by mem- 

 bers of its biological school to the uttermost parts of the earth, with 

 the sole purpose of studying the growth from the egg of strange and 

 interesting animals, only to be obtained in the remote regions thus 

 visited. Mr. Caldwell, Fellow of Caius College, has gone to Austra- 

 lia, and is still there, for the purpose of studying the history of the 

 growth from the egg of the duck-billed Platypus or duck-mole ( Or- 

 nithorhynchus) and the spiny ant-eater (Echidna), as well as of the 

 extraordinary lung-bearing, and therefore air-breathing, fish of Queens- 

 land known as the Barra-munda ( Ceratodus Forsteri). Mr. Adam 

 Sedgwick, Fellow of Trinity College, went in 1883 to the Cape of 

 Good Hope expressly for the purpose of collecting live specimens and, 

 if possible, eggs and young, of a creature very much like a caterpillar 

 in appearance, and known as Peripatus. He obtained the most com- 

 plete success, brought home to England three hundred living speci- 

 mens of the extraordinary Peripatus, and has obtained from them since 

 they have been in England young in all stages of development, which 

 will enable him very soon to give a most valuable account of the 

 growth from the egg of this strange form. A third member of the 



