212 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
CHIMAHBRA Layne, 1754, 1758. 
Six living species of this genus are recognized. 
Chimaera monstrosa Linné, 1754, 1758. 
Chimaera phantasma Jordan & Snyder, 1900. 
Chimaera affinis Capello, 1868. 
Chimaera colliei Lay & Bennett, 18389. 
Chimaera ogilbyi Waite, 1898. 
Chimaera mitsukurii (Dean) Jordan & Snyder, 1904. 
The synonymy of Chimaera monstrosa includes C. argentea Ascan., 1772, 
C. borealis Shaw, 1804, C. mediterranea Risso, 1826, C. cristata Faber, 1829, 
and Callorhynchus centrina and Call. atlantica of Gronow and Gray, 1854; and 
that of Chimaera affinis contains C. plumbea Gill, 1877, and C. abbreviata Gill, 
1883. 
Chimaera monstrosa and C’. phantasma have the anal fin distinct from the sub- 
caudal; they differ in this respect from the other species. One of the latter, 
C. colliei, has been made the type of a new genus, Hydrolagus, by Gill, 1862. 
This genus was originally ‘“ distinguished from Chimaera by the absence of an 
anal fin and the triple division of the sexual organ of the male.” The absence 
of the triple division of the clasper is more apparent than real, since the carti- 
lage of that organ is trifid in males of all the species of the genus. On 
Chimaera colliei two of the divisions of the cartilage are wrapped together by 
the skin so as to present the appearance of a single division. If absence of 
the anal fin is to make generic separation necessary, then Chimaera affinis 
would be placed with C. collici, though actually farther removed by structure 
from the latter than C. monstrosa, As may be seen by comparison of the 
figures published here, in dental characters and in those of the brain and the 
skeleton Chimaera colliei agrees closely with C. monstrosa. In some respects 
Chimaera mitsukurii accords with C. colliei, as in the apparently bifid claspers 
and the lack of an anal fin, but it has a much longer caudal filament than that 
species. 
The right of Chimaera to be considered the most differentiated of the Chis- 
mopnea will hardly be questioned. By rostrum, dentition, brain, claspers, and 
lateral system it is the farthest removed from Rhinochimaera. 
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