Certain passages were difficult to translate. Most troublesome were: 

 saiCOHOMepHOCTB % which literally is "lawful measure" but which may be translated 

 variously as- -conformity with law, regularity, principle, normality; and sepKaJbHUfi , 

 which is translated as smooth or bilaterally symmetrical. In the case of the former 

 word, several alternative translations are usually given where it occurs in the text. 

 Where a different English phrase seems to fit Dr. Bychowsky's meaning better or 

 serves to clarify the text, it has been inserted in parentheses with the Latin notation 

 nobis- -by us. To avoid lengthy rendition of the original, we have at times used new 

 words the meaning of which seems, nevertheless, clear. For instance, we have 

 translated mnogoletnil by polyannual to designate a cycle which lasts many years, and 

 segoletki by young of the year to designate fishes which are less than one year old. 

 Certain obvious errors or misspellings in the original text were changed, less obvious 

 ones are noted with (si£). 



The bibliography was divided into two parts, Russian and non-Russian, 

 in the original and has been retained that way in the translation. The Library of Con- 

 gress system for the spelling of the names of Russian authors has been followed In 

 the bibliography. When the name of the author was spelled differently in a previous 

 translation, the alternate spelling follows our transliteration. The reason for this is 

 that for purposes of research it is preferable to follow the system of the Library of 

 Congress which indicates variant spellings. 



To prevent misunderstanding which may have arisen from the preserva- 

 tion of Russian letters used In the original to Identify the drawings, we replaced, in 

 the translation, Russian letters by those of the English alphabet, for instance, Russian 

 B by English C, etc. To clarify further this substitution, we have reproduced on page iv 

 both alphabets. In so doing, we do not think It out of place to include in parentheses 

 after Russian letters the symbols used for their transliteration. The numerals between 

 the alphabets indicate the relative place of each letter in Its respective alphabet. 



Though the Latin morphological terms are not italicized in the Russian 

 text, we prefer to do so in the translation. 



For convenience in referring to the Russian text the original pagination 

 is given in the margin of the translation opposite the place where the new page begins. 

 Occasionally figures or tables are somewhat displaced from their original page loca- 

 tion; however, since they, themselves, are numbered sequentially, no confusion 

 should result. 



VI 



