OF THE DOGS, WOLVES, AND FOXES. 



273 



306 



307 



308 



509 



Flos. 306, 307. Cania dingo Oxyhemoglobin. 

 FIGS. 308, 309. Canit caane Oxyhemoglobin. 



Oxyhemoglobin of Cam's dingo. 



Orthorhombic: Axial ratio a : b : 6 = 0.6009 : 1 : 0.2582; a : i =1 : 0.4296. 



Forms observed: Unit prism (110), macrodomes (101), (504), (302); basal pina- 

 coid (001). 



Angles: Unit prism angle 110AlTO=61 30'; macrodome 10lAT01=46; macro- 

 dome 504 A 504 =56 30'; macrodome 302 A 302 =66, about (65 36' calculated). 



Habit prismatic on the vertical axis, the crystal consisting of the unit prism (110) 

 terminated by a zone of macrodomes (101), (504), (302) (text figure 306), of which either 

 one may predominate, but the common ter- 

 mination is the unit dome (101) (text figure 

 307). The crystals are normally much 

 shorter than is common in this genus and 

 vary in ratio of length to thickness from 20 : 1 

 to 4 : 1 or even less. The normal crystals 

 usually range between 20 : 1 and 15 : 1. 

 Along the protein ring and the cover edge the 

 crystals are much larger and stouter, and are 

 vertically striated, due to parallel growth. 

 Groups of two crystals united on the brachy- 

 pinacoid in parallel growth are particularly 

 common among these larger crystals, but 

 the majority of them are more complicated 

 groups. The greater part of the crystals 

 occurring in the body of the slide are simple 

 and unstriated, and doubly terminated. 

 They appear to twin upon a pyramid face as 

 contact twins, but do not unite in spherulitic or radiating groups, as is common in the dogs. 



Pleochroism is marked when a and c lie in the section, but weak when b and c are 

 in the section, indicating that 6 and c are near together in index, but a is rather far from 

 either. The pleochroic colors are: a pale rose; & deep rose, c deep blood-red. In ordinary 

 (unpolarized) light the color of the crystals is the usual Oxyhemoglobin red. Looking 

 along a the double refraction is quite weak, but in other aspects it is moderately strong. 

 Extinction is straight in all aspects. On the flat of the prism, looking along a the biaxial 

 interference figure is seen, with not very widely separated brushes. The orientation of 

 the elasticity axes is a =a; & =6; c =6. The plane of the optic axes is the brachypinacoid. 

 The acute bisectrix of the optic axes is the axis of greatest elasticity, Bx a = a, and the 

 optical character is hence negative. 



AZARA'S WILD DOG, Cam's azarce. Plate 76. 



The specimen of blood was received during the summer from the New 

 York Zoological Park, and was kept frozen in the refrigerating plant until 

 examined. The blood was very putrid and was practically a mass of crys- 

 tals when the collecting tube was taken from the cold storage. The blood 

 was mixed with an equal volume of a 50 per cent solution of egg-white 

 and subjected to action of oxygen until thoroughly saturated and the color 

 had changed to bright red. It was then centrifugalized for 2 hours, and the 

 slide preparations made as usual. Crystals of Oxyhemoglobin formed very 

 readily and showed no signs of dissolving. About 20 hours after the slides 

 were prepared the photomicrographs were made. Spectroscopic examina- 

 tion showed the presence of reduced hemoglobin in the solution, but the 

 crystals showed only the spectrum of Oxyhemoglobin. 



is 



