cxxxiv GENERAL SUMMARY OF SCIENTIFIC AND 



hybrids between the canvas-back and the mallard was nearly 

 twice the size of either parent; and this is equally true of 

 the Cayuga hybrid. 



It is often claimed that if the care of man be withdrawn, 

 an improved breed will retrace the steps of its ancestry and 

 revert to its original characteristics. For some years Pro- 

 fessor Brewer has been investigating this subject, and seeking 

 for proof of the alleged tendency to reversion. To carefully 

 worded inquiries in writing, following upon every report of 

 such " reversion," Professor Brewer lias received very numer- 

 ous replies, and they are unanimous in the negative. This 

 is certainly remarkable, following upon the confident asser- 

 tions that animals so frequently exhibited the alleged tend- 

 ency. The inquiries were pushed in the specific localities 

 where the reversion was said to have occurred ; the ques- 

 tions have been put to a large number of stock-breeders, and 

 finally have been made by means of a printed circular. 

 But the result was always the same, except that a smile of 

 incredulity extended over the faces of some stock-breeders 

 when such inquiries were put to them, and they feared they 

 were to be made the victims of a "sell." No instances of 

 the alleged "reversion" having been authenticated in Pro- 

 fessor Brewer's experience, he asked the association to aid in 

 exposing and refuting the pernicious notion. 



Besides the ordinary normal mode of reproduction, sev- 

 eral genera of the phyllopod Crustacea are known to repro- 

 duce by what is termed by Professor Owen parthenogenesis, 

 or virgin reproduction ; i. e., the eggs arise from the ovary by 

 a budding process, like the budding of leaves on a tree, 

 through the simple multiplication of cells, without fertiliza- 

 tion by the male spermatic cell. This occurs in several in- 

 sects, as in the Ajyhis, the honey-bee, the silk-moth, etc., and 

 in Daphnia, the water-flea, and in other Entomostr 'a xa. 



A Russian naturalist, Schmankiewitsch, in 1872 discov- 

 ered a variety of " Branchipiis" (Artemia) arietinus near 

 Odessa. In the summer and autumn of the vear before lie 

 noticed that this Artemia changed its form, corresponding to 

 the o-reater or less saltness of the water. In summer, when 

 the water was most salt, there was a retardation in growth ; 

 and this retardation was the more evident the hio;her the 

 temperature and the more concentrated the solution of salt. 



