CHAPTER IX. 



CRYSTALLOGRAPHY OF THE HEMOGLOBINS OF PISCES, 

 BATRACHIA, AND REPTILIA. 



While this research is mainly upon the hemoglobins of mammals, 

 certain species of fish, batrachians, reptiles, and birds were investigated, 

 in order that it might be seen whether the results obtained for mammals 

 extended to these classes also. Only a very limited number of species 

 were examined, including 4 fish, 1 batrachian, 1 reptile, and 10 birds; 

 but the results are entirely in conformity with those obtained from the 

 examination of mammalian blood, as indicating the specific character of 

 the properties of the hemoglobin in each species. In most cases the 

 species were too far separated from each other to show similarities due to 

 their zoological affinities, such as are shown in the hemoglobins of mam- 

 malia, but in the case of the birds the relationship was sufficiently close 

 to bring out family and generic characteristics. 



PISCES. 

 BARNDOOR SKATE, Raia Icevis. Plate 1. 



One species of the selachians or cartilaginous fishes, the barndoor 

 skate, Raia Icevis, was examined. This skate was sent to the laboratory 

 from the New York Aquarium, and the blood was extracted by the dis- 

 section of the dead fish. The blood was oxalated and centrifugalized, the 

 corpuscles were ether-laked, a little water was added, and the mixture 

 again centrifugalized. From the clear solution thus obtained the slide 

 preparations were made. The crystals developed readily and were oxy- 

 hemoglobin, as determined by spectroscopic examination. They occur in 

 single crystals and in sheaf-like or branching aggregates of these crystals. 

 The individual crystals are rhombic plates. 



The crystallographic description is as follows : 



Oxyhemoglobin of Raia Icevis. 



Orthorhombic: Axial ratio a : b : 6 =0.6008 : 1 : 0.4024. 



Forms observed: Prism (110), base (001), and from twins the unit pyramid (111) 

 and a macrodome (401). 



Angles: Prism angle 110AlTO=62; prism to base 110 A 001 =90; prism to 

 pyramid 110 A 111=38; macrodome to base 401 A 001 =69 (calculated 69 33'). 



Habit thin tabular on the base (001), the crystals being a very short prism (text 

 figures 1 and 2). Twinning is on the pyramid (111); this form was only observed in 

 twins; or on the macrodome (401), a form also only observed in twins. Also in crystals 

 grown together on the base into groups, which, seen on the edge aspect of the plate, 



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