38 A JOURNEY IN BRAZIL. 



long tapering tail of the skate. Were it only that they 

 enable us to set aside all arbitrary decisions and base our 

 classifications on the teachings of nature, these investigations 

 would be invaluable ; but their importance is increased 

 by the consideration that we are thus gradually led to 

 recognize the true affinities which bind all organized beings 

 into one great system." 



April 20th. The day after to-morrow we shall enter 

 the Bay of Rio de Janeiro. One begins to see already 

 that little disturbance in the regularity of sea life which 

 precedes arrival. People are making up their letters, and 

 rearranging their luggage ; there is a slight stir pervading 

 our small party of passengers and breaking up the even 

 tenor of the uniform life we have been leading together 

 for the last three weeks. It has been a delightful voyage, 

 and yet, under the most charming circumstances, life at 

 sea is a poor exchange for life on land, and we are all 

 glad to be near our haven. 



On Tuesday the lecture was upon the formation and 

 growth of the egg ; a sort of practical lesson in the study 

 of embryology ; yesterday, upon the importance of ascer- 

 taining, at the outset, the spawning season of the animals 

 in Brazil, and the means to that end. " It will often be 

 impossible for us to learn the breeding season of animals, a 

 matter in which country people are generally very ignorant. 

 But when we cannot obtain it from persons about us, 

 there are some indications in the animals themselves 

 which may serve as a guide. During my own investiga- 

 tions upon the development of the turtles, when I opened 

 many thousands of eggs, I found that in these animals, 

 at least, the appearance of the ovaries is a pretty good 

 guide. They always contain several sets of eggs. Those 



