250 CRYSTALLOGRAPHY OF THE HEMOGLOBINS OF THE 



Oxyhemoglobin of Otaria gillespii. 



Monoclinic hemimorphic or monoclinic sphenoidal (tartaric-acid type) : Axial ratio 

 a : b : 6 = 0.7883 : 1 : 1.7314; /?= 74. 



Forms observed: Pyramid of unit series, not measured, may be called unit pyramid 

 (111), unit prism (1TO), orthopinacoid (100), clinodome (Oil), base (001). 



Angles: Traces of unit pyramid on base, edges llT-001 A Tl 1-001 =76 30', or 

 edges llT-001 A lTO-001 =103 30'; traces of unit prism on base at opposite pole, 

 edges 110-001 A TTO-001 =76 30'. The angle of the clinodome was not accurately 

 determined, but was very near 60. The angle of the orthopinacoid to base 100 A 001 = 

 73 30' to 74 =0. 



Habit tabular on the base and elongated on the ortho-axis, the crystal consists of 

 the base bounded by the orthopinacoid and at the positive end of the ortho-axis the 

 unit pyramid, while at the negative end of this axis is found the unit prism and the 

 clinodome (text figures 258 and 259). The crystals show a tendency to grow together 

 in radiating groups uniting at the negative end of the ortho-axis and also in parallel 

 growth on the base, piling upon each other in perfect orientation. These groups in parallel 

 growth also expand along the clino-axis, frequently with the prism and clinodome planes 

 in common, but the pyramid planes showing the parallel growth (1559). Twins on the 

 clinodome are common, the angle being nearly 60; they form in trillings, very frequently 

 radiating from a common axis, the common clinodome edge (text figure 260). The 

 hemimorphic character is found in the smallest crystals as well as in the larger ones, and 

 there is not much change of shape of the crystals as they grow from small to large size. 



Pleochroism is strong; a nearly colorless, b rather strong red, c deep red. Double 

 refraction is fairly strong, extinction is straight or nearly so in all ordinary aspects. The 

 orientation of the elasticity axes is a=a or veiy nearly, b=6, c A 6 = about 16 30' in 

 the obtuse angle or the angle =90-/?; hence the axis c is nearly or quite normal to the 

 base (001). The plane of the optic axes is the clinopinacoid and the acute bisectrix is 

 the axis of greatest elasticity; Bx a = a and the optical character is negative. The axial 

 angle 2=35 to 40. 



CO-hemoglobin of Otaria gillespii. 



Monoclinic hemimorphic or monoclinic sphenoidal (tartaric acid type) : Axial 

 ratio a : b : c =0.7883 : 1 : 1.7314; /3 = 74. 



Forms observed: Unit pyramid (111), unit prism (1TO), clinodome (Oil), ortho- 

 pinacoid (100), base (001). 



Angles: Traces of unit pyramid or of unit prism on base 76 30' actual angle, or 

 103 30' normals as measured at the ends of the ortho-axis, making the edges of these 

 two unit forms on the base llT-001 A 110-001 = 103 30' as recorded for the oxyhemoglo- 

 bin; clinodome angle Oil A OTT = 60 to 61 (taken as 60 in calculation of the axial 

 ratio); orthopinacoid to base 100 A 001 =74=/3. The pyramid called unit on the base, 

 angle 111 A 001, was not obtained. 



Habit tabular on the base and elongated on the ortho-axis, exactly as described 

 for the oxyhemoglobin (text figures 258, 259). The crystals grow in groups and in regular 

 growths as there described, but are much more perfect. 



Twins and trillings are very common on the clinodome as described under the 

 oxyhemoglobin; the angle of the trilling is generally 120, but some were 121, 118, 

 perhaps not quite in symmetrical position (text figure 260). These twins show a cyclic 

 arrangement of the unit pyramid planes, the three planes of the unit pyramid on one side 

 of the trilling being corresponding planes. 



The crystals are strongly pleochroic; a colorless, b old rose, c deep crimson. Double 

 refraction is rather strong, except on edge views looking along the axis of greatest elas- 

 ticity. Extinction is straight with the basal edges and symmetrical on the base, as though 

 orthorhombic. The orientation of the elasticity axes is the same as in the oxyhemoglobin, 

 a=a, b=6, c A <! = 16. The plane of the optic axes is the plane of symmetry; on the 

 base a biaxial figure is obtained with brushes that pass out of the field indicating the 



