OTARIID^E, PHOCID.E, MUSTELID^, PROCYONID^E, AND URSID^E. 249 



coid was so strongly developed as to produce a prismatic habit on the ortho-axis, the 

 crystal being 5 to 10 times as long on this axis as on the clino-axis. The plates were 

 generally rather thin ; edge views showed a ratio of length on the ortho-axis to the thick- 

 ness of the plate of 10 : 1 or more, but in some cases this became 5:1. The crystals 

 grow singly or in radiating groups, showing a tendency to twinning on the clinodome; 

 but this plane was not developed and there were no definite twins made out. Parallel 

 growth by piling up on the base and the group extending along the ortho-axis was a 

 very common habit in the larger crystals. 



Pleochroism is hardly noticeable on the flat aspect of the plates, but quite strong 

 on edge views. The colors are: a pale red, b and c nearly equal and deep red. The 

 orientation of the elasticity axes is a = i, b=6, c A a = 15, in the obtuse angle. The 

 plane of the optic axes is the plane of symmetry. On the base, in convergent polarized 

 light, one brush of a biaxial interference figure is seen and traces of the other. The acute 

 bisectrix of the optic axes is the axis of greatest elasticity, Bx a =*a and the optical char- 

 acter is hence negative. 



FIOB. 256, 257. 1'hucu vitulina Oxyhemoglobin. Flos. 258, 259, 260. Otaria gttletpii Oxyhemoglobin (first orientation). 



CALIFORNIA SEA-LION, Otaria gillespii. Plates 63 and 64. 



Specimens of the blood of the sea-lion were received from the National 

 Zoological Park at Washington and from the New York Zoological Park. 

 In both cases the blood was rather stale, and in one case it was clotted. 

 The specimens were oxalated and laked with ether, and cleared by centrif- 

 ugalizing for several hours. From the clear blood slide preparations were 

 made in the usual manner. The blood crystallized at room temperature, 

 and the crystals did not readily dissolve on slight increase of temperature. 

 Bacteria in the preparations destroyed the crystals after some days. A 

 preparation of CO-hemoglobin kept well and developed very fine crystals. 

 From these the most satisfactory measurements were obtained. The crys- 

 tals grew to much larger size than was the case with the oxyhemoglobin 

 crystals in the other preparations, and the planes of the crystals were per- 

 fectly developed. The angles, as far as they could be measured in the oxy- 

 hemoglobin crystals, corresponded to the good measurements obtained from 

 the CO-hemoglobin crystals, and the optical characters appeared to be 

 identical. The crystallographic and optical constants are hence derived 

 from the CO-hemoglobin with greater exactness. 



