ZOOLOGICAL APPLICATIONS OF THIS METHOD OF RESEARCH. 



335 



cerned no close relation is indicated. The crystals of the dogs all belong to 

 the orthorhornbic system, normal group, while those of the bears, as above 

 stated, are monoclinic sphenoidal, thus indicating very different forms of 

 structure for the two. On the other hand, the bears appear to be related 

 to the Mustelidce, as well as to the Otariidce and Phocidce. So small a number 

 of species of these groups have been examined that any positive statements 

 of relationships are probably premature, but the above indicated relation- 

 ships are certainly suggested by the crystals. 



Among the birds certain anomalies were noted. The guinea-fowl is 

 classed as belonging to the Gallince, but its blood crystals seem to be more 

 nearly like those of the ostrich, which is placed in a separate subclass. 

 The other two members of the Gallince, the chicken, Gallus domestica, and 

 the quail, Colinus virginianus, have crystals that closely resemble each 

 other. A comparison of the crystallographic characters of the hemoglobins 

 of the four species above mentioned will make these relations clear: 



TABLE 56. 



These figures perhaps rather indicate the non-relationship between the 

 guinea-fowl and the chicken or the quail than the relationship between 

 the guinea-fowl and the ostrich; although, as the ostrich is a bird in which 

 the wingless character, which places it in a separate subclass, is evidently 

 the result of degeneration, there is no reason to believe that it and the 

 guinea-fowl may not have had a common ancestor. 



On comparing the crystals of the few species of primates that were 

 examined, a striking similarity may be seen between the a-oxyhemoglobin 

 crystals of the baboons and those of man. The /3-oxyhemoglobin crystals 

 found in the baboons were not observed in the crystals from the human 

 species, but the y-oxyhemoglobin crystals of the baboons closely resemble 

 the corresponding crystals observed in human blood. In this case the 

 parallelism of the crystals from the two genera is shown in two kinds of 

 oxy hemoglobin crystals. 



By some zoologists the bats have been placed among the primates, 

 and the relationship of the two groups has been claimed by a number of 

 zoologists. The crystals of oxyhemoglobin from the brown bat do show 

 a considerable resemblance to the oxyhemoglobin crystals of the genus 

 Papio, but on the other hand the fruit-bat examined showed quite a differ- 

 ent type of crystal. 



A striking example of the application of this method of comparing the 

 crystals of the hemoglobins of different species to demonstrate relationships 

 is shown in the rats. The first species of rat examined was the domesticated 

 white rat. Later, the Norway rat and the black and Alexandrine rats were 



