182 CRYSTALLOGRAPHY OF THE HEMOGLOBINS 



Oxyhemoglobin of Dasyurus viverrinus. 



Monoclinic (?): Axial ratio a : b : 6 =1.7856 :!:<!; /?=69. 



Forms observed: Prism (110), base (001), clinopinacoid (010). 



Angles: Prism angle, traces of the prism on the base =58 30', base to prism 

 edge=/3 = 69. 



Habit long and short prismatic, the prism often flattened on two faces, producing 

 a strongly triclinic habit (text figure 80), elongated in the direction of the 6 axis; also in 

 symmetrical prisms long or short and terminated by the base (text figure 81). Some crys- 

 tals show also the plane of symmetry, (010), in combination with the prism and base (text 

 figure 82). Twins are very common, on the narrow prism face, and making an elongated 

 geniculated twin or sort of V-shaped trough, the faces 110 and TTO being in contact 

 (text figure 83). Plates in which the base is the large plane do not appear to be common. 



Pleochroism rather strong, the colors ranging from pale yellowish-red to deep red; 

 a pale yellowish-red, b deeper red, c deep red. The extinction angle was not exactly 

 observed; c A 6 about 12 or more. On crystals when the plane of symmetry is pre- 

 sented on edge the extinction is straight. The axial plane is the plane of symmetry and 

 the orientation of the axes, not very exactly determined, was approximately a A o = 

 about 9 in the obtuse angle; b=b, c A <!=12 about in the obtuse angle. The inter- 

 ference figure was not observed and the optical character was not determined. It appears 

 to be positive, judging from the pleochroism and the elasticity. 



The strong triclinic habit of these crystals as they at first appeared led to the sup- 

 position that they were really triclinic, but further examination of the later crystals 

 and of the photographs seems to indicate that they are really monoclinic, but appear 

 triclinic through unsymmetrical development. They do not show the development of 

 these plates on the base as is usual in plate-like crystals, but they show only the flattening 

 on a pair of prism faces, which is not common. 



TASMANIAN WOLF, Thylacynus cynocephalus. Plate 20. 



The blood was stale when received, it was thick and beginning to 

 putrify. It was diluted with an equal volume of water and centrifugafized 

 for one experiment, also ether-laked and centrifugalized for another. In 

 all cases the preparations were made in the usual manner. The crystals 

 were allowed to form at temperatures near C. and up to 5 or 6 C. The 

 crystals formed readily, soon after covering, and were at first small plates, 

 which afterwards increased in size. These were a-oxyhemoglobin. In 

 many slides on standing for some days a second crop of crystals developed; 

 these were isometric dodecahedra, the only isometric crystals thus far 

 observed in the blood of any species. They were also oxyhemoglobin, 

 and are described as /^-oxyhemoglobin. All determinations of the character 

 of the crystals were made with the Zeiss microspectroscope, and the spectra 

 of these two varieties of oxyhemoglobin did not differ as far as could be 

 observed. The blood after standing in a test-tube exposed to the air at near 

 C. for some days developed the crystals of ^-oxyhemoglobin simultane- 

 ously with the crystals of the a-oxyhemoglobin. 



a-Oxyhemoglobin of Thylacynus cynocephalus. 



Monoclinic: Axial ratio not determinable. /3=77. 

 Forms observed: Clinopinacoid (010), orthopinacoid (100), base (001). 

 Angles: 010 A 100=90; 010 A 001=90; 100 A 001=/3 = 77. 

 Habit thin tabular, by development of the plane of symmetry; the plates being 

 very thin and showing a tendency to elongate in the direction of the clino-axis (text 



