188 



MARSUPIALIA, EDENTATA, AND SIRENIA. 



The colors are rather pale; pleochroism is quite strong; a pale yellow, b deep pink, 

 c deep rose-pink or rose-red; b and c are nearly the same tint. Absorption is in the 

 order c > b > a. Extinction is straight on (100) and on (010). The orientation of the 

 elasticity axes is fl=a; b=6; ( = 6. No interference figure was seen on b; but on a, or 

 looking along a, traces of a figure were seen, the brushes passing out of the field in open 

 position. The aspect looking along c could not obtained, but there seems to be no doubt 

 that Bx a c, or that the optical character is positive. 



The axis of <J=c is evidently the axis of least cohesion, as is shown by the cleavage 

 and by the solution of the crystals in this direction. The axis of greatest elasticity a is 

 the direction in which the crystals develop after the full length has been attained. 



SIRENIA. 



MANATEE, Manatus americanus. 



Oxalated blood was received from the New York Zoological Gardens, 

 and was prepared as usual. The crystals are very soluble and dissolve 

 rapidly when brought into a warm room. 



Oxyhemoglobin of Manatus americanus. 



Orthorhombic : Axial ratio 0.949 : 1 : (5. 



Forms observed: Unit prism (110), macropinacoid 

 (100), base (001). 



Angles: Prism angle 110 A 1TO=95 (85 normals) ; 

 prism to base 110 A 001 =90. 



Habit tabular, elongated parallel to the macro-axis, 

 the prism faces and the macropinacoid often in equilib- 

 rium (text figures 103 and 104). 



Pleochroism was difficult to observe, owing to the 

 high color of the plasma, but evidently the color is deeper 

 parallel to the 6-axis (c). Extinction is symmetrical on 

 the flat views of the plates and straight on edge views. 

 Orientation of the elasticity axes is a = 6, b=a, c=6. The 



interference figure was not observed, the crystals dissolving while under observation. 

 The optical character was hence not determined. 



TABLE 39. Crystallographic characters o} the hemoglobins of the Marsupialia, Edentata, and Sirenia. 



104 



ib 



Fioa. 103, 104. Manatua americanus 

 Oxyhemoglobin. 



