260 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
The Brain, Plates 14, 15. 
The brain of recent Chimaeroids is crowded together posteriorly. The 
optic and inferior lobes are close to the medulla oblongata and are below the 
cerebellum. The hemispheres are remote from the optic and inferior lobes, 
and the connections with them are slender and nerve-like. This shape of the 
brain, the massing that has taken place backward with the remoteness that 
obtains forward, is characteristic of the group, so far as known living genera 
are concerned. A similar crowding of parts of the brain is common among 
Plagiostomes, but the wide separation of the hemispheres from the optic lobes 
is peculiar to Chimaeroids. In some genera of the latter the olfactory bulbs are 
distant from the hemispheres, so also in particular Plagiostomia, but in one 
genus each hemisphere is closely connected with an olfactory bulb. In these 
cases either remoteness or the absence of separation of the olfactories serves 
to distinguish the genera, 
The brain of Rhinochimaera pacifica, Plate 14, from the medulla oblongata 
forward to the optic lobes differs comparatively little from that of its allies. 
The posterior mass is similar in shape and in the positions of its component 
parts. Compared with Chimaera colliei, Plate 15, Figures 1 and 2, or Callo- 
rhynchus milii, Figures 4 and 5 of the same plate, the brain of the present 
specimen is somewhat smaller in the cerebellum, which does not cover the 
optic lobes so completely as in the other cases; this deficiency in size, however, 
may be a feature of the individual and not a character of the species. The 
nerve-like connections with the hemispheres are more slender in Rhinochimaera 
than is the case in the other genera. In the distance between hemispheres 
and olfactory bulbs Rhinochimaera pacifica agrees with Callorhynchus milii, 
Plate 15, Figures 4 and 5, though the connections are even more slender than 
in the latter species and the olfactory bulbs are smaller. Between the hemi- 
spheres and the olfactory bulbs in Rhinochimaera the distance is about twice 
that between the hemispheres and the optic lobes; in Chimaera colliei the dis- 
tance between olfactories and hemispheres has vanished, while that between 
the latter and the optic lobes remains. Similar comparisons may be made with 
the brain of Chimaera monstrosa, which has been worked out by Dr. Wilder 
and others. 
Miscellaneous. 
The first mention of the species described above, and a full-grown male of 
which is figured on Plate 1, in one-third of its life size, was published-by Pro- 
fessor K. Mitsukuri in the Tokyo “ Zoological Magazine,’’ No. 80, Vol. VIL, 
June, 1895, with an outline sketch on Plate 16 of the same volume. The more 
important portion of this notice, containing all the description, is reprinted 
below. By some mistake the outlines were said to be those of a male; they 
are evidently those of a female. Professor Mitsukuri’s remarks are given in 
his own words : — 
