system used ix breeding guinea-pics and rabbits. 313 

 Indices. 



The above two record sheets are all that are necessary in 

 this pedigree system. However it is convenient to have at least 

 one index. This is an index to the matings into which any ani- 

 mal has entered. For this the numbers of the animals are 

 stamped in consecutive order in alternate columns on loose leaf 

 sheets. \Mien any animal is mated the number of this mating 

 is entered opposite the number of the animal. Thus we can 

 see at once all the matings into which an animal has entered 

 without having to look up its individual description sheet. 



For some purposes it is also convenient to have an index 

 showing the mating from which each individual arose. Neither 

 of these indices is necessan,^ for the completeness of the record. 



The operation of this pedigree system may be illustrated by 

 an example. Thus we may pick up the gxiinea-pig bearing the 

 number 231 on its ear tag and we wish to know its family and 

 breeding record. \\t first turn to page 231 of the individual 

 description book. This gives the animaKs description, sex, date 

 of birth, etc. The description can be verified, if we wish, by 

 glancing at the marks on the outline figure Ccf. fig. 146). This 

 page also shows that tliis animal cam(; from mating number 

 81 and that it has entered twice in mating number 114 and once 

 in mating number 147. On page 81 of the mating book are 

 given the numbers of the parent? of this individual as well as 

 its full brothers and sisters. The more remote ancestors may 

 be traced through the parent numbers. On pages 114 and 147 

 of the mating book will be found all the offspring of this indi- 

 vidual as well as the numbers of the individuals with which it 

 was mated. If any of these offspring have been mated, such 

 mating numbers will appear in the proper columns on these 

 pages. In this way the grandchildren and more remote off- 

 spring can be traced at once. Reference to the ex]>eriment 

 number and autopsy number makes the record complete at 

 every point. 



The operations in describing and recording an individual are 

 relatively simple. Several cross references must be made but 

 this involves but little time. The indices mentioned above aid 

 in the ease with which this can be done. 



