CHAPTER XI. 



CRYSTALLOGRAPHY OF THE HEMOGLOBINS OF THE 

 MARSUPIALIA, EDENTATA, AND SIRENIA. 



Nine specimens of the Marsupialia were examined, including repre- 

 sentatives of the following families: 



Didelphyidce: 1 species, the common opossum, Didelphis virginiana. 



Dasyuridce: 4 species, the Tasmanian devil, Sarcophilus ursinus; 



the spotted dasyure, Dasyurus maculatus; the Australian cat, 



Dasyurus viverrinus; and the Tasmanian wolf, Thylacynus 



cynocephalus. 



Phalangeridce : 1 species, the vulpine phalanger, Trichosurus vul- 



pecula. 



Macropodidce : 3 species, the rat-kangaroo, Mpyprymnus rufescens; 

 the kangaroo, Macropus giganteusC?) ; and the rock-kangaroo, 

 Petrogale sp. 



The normal crystals of every species of marsupial examined are mono- 

 clinic, and only in 2 of the 9 species examined were crystals of other systems 

 observed. One of these was a /3-form of oxyhemoglobin found in the opos- 

 sum and the other a /3-form of oxyhemoglobin which developed in the 

 blood of the Tasmanian wolf. Comparing the crystals of the Pohjprolo- 

 dontia, to which the opossum, dasyurus, Tasmanian devil, and the Tas- 

 manian wolf belong, a close resemblance can be traced in the form of all 

 the species except the Tasmanian wolf, and in this species the development 

 of the crystals was such that direct crystallographic comparison with the 

 other species .was not possible, as no axial ratio could be determined. In 

 the species in which this constant was determined it was found to vary for 

 the axis a from 1.7856 in the opossum and Australian cat to 1.8047 in the 

 Tasmanian devil for oxyhemoglobin, a variation that was considerably 

 less than the difference between the a-oxyhemoglobin and the reduced 

 hemoglobin in the opossum (1.7856 and 1.963). The optical character of 

 all of these species is the same, with the exception of the Tasmanian wolf. 

 The crystals of the Diprotodontia (including the phalangers and the 

 kangaroos) showed the kangaroos (Macropodidce) forming one group, and 

 the phalanger apparently closer related to the Didelphyidce and the Dasyu- 

 ridce in ratio, while the phalanger form recalls the Tasmanian wolf crystals 

 of which no ratio was obtained. The kangaroos examined belonged to the 

 genera Macropus, JEpyprymnus, and Petrogale, and they naturally showed 

 some variation, but formed a fairly close group. 



In this chapter there is also included the description of one species of 

 the Edentata and one of the Sirenia which naturally do not show any very 

 close resemblance to the Marsupialia nor to each other. 



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