PLATE 51 



303 



304 





305 



306 



301. Oxyhemoglobin of the Beaver (Castnr canailcnsis), showing rhomhoi.lal and hexagonal tabular 



crystals, on base and edge. 



302. Same, showing four and six-sided tabular crystals in different aspects and small hexagonal 



plates of mimetic twin. 



303. Same, large hexagonal plates, showing twinning and parallel growth. 



304. Same, elongated crystals showing twinning. 



305, 306. Oxyhemoglobin of the Muskrat (Fiber zibethicus), showing needle-like first-formed crystals with 

 elongated horse-type twins of lath-shaped crystals. 



