250 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
which latter passes down behind the eye, and connects directly with the cra- 
nial ; this places the short occipital behind the aural, and consequently the orbital 
does not meet the cranial. On Plagiostomes and on bony fishes the occipital is 
in front of the aural, and the orbital meets the cranialat some distance in front 
of the aural. In one case the occipital can be regarded as a portion of the 
lateral line, in the others it must be considered as a continuation of the cranial 
branch. On Chimaeroids again, the mouth being forward from the eye, the 
angular branch passes down and forward from the orbital to meet the narial, 
but on Plagiostomia having the mouth backward from the eye the angular passes 
backward. In the Rhinochimaeridae the canals have the appearance of tubes 
that have been longitudinally slit on the outer side, Plate 4, Figure 3; they are 
thus intermediates between the more open grooves of the Chimaeridae, and the 
tubes of the Callorhynchidae. As is seen on Rhinochimaera, Plate 1, Figure 1, 
the jugular meets the orbital, and the angular descends from the orbital and 
passes downward and toward the front to meet the nasal and the oral; the 
same is true in Harriotta, Plate 2, Figure 4. In Chimaera the oral meets the 
angular, Lat. Canal Syst., Plate II, Figures 3 and 4, but on Callorhynchus it 
starts from the orbital, 1. c., Plates IIT. and IV., Figure 1. On both Mhinochi- 
maeridae and Callorhynchidae the jugular starts from the orbital ; on Chimae- 
ridae it starts either from the angular or the orbital. On the individual from 
which the description of Rhinochimaera is taken, the aural is not continuous 
across the head, but is in two parts, which pass one another and overlap for 
some distance, Plate 2, Figure 1 ; the ecranials and rostrals pass from the junction 
of-aurals and occipitals forward to the end of the snout, bending toward one 
another between the eyes; the subrostral lies at the side of the snout and meets 
the orbital below the middle of the orbit ; the oecipital passes down and back- 
ward from the aural; the orbital goes down and forward from the occipital ; 
and the angular goes down, then bends forward to the oral and the nasal. The 
jugular meets the orbital, and, like the oral, is more or less broken and dis- 
connected behind the symphysis. On this specimen the narials of the two 
sides are continuous across the lower side of the snout, forming the only com- 
plete connection, except the neural, between the system of the right side and 
that of the left. On specimens of Harriotta the narials appeared somewhat 
broken at this point, orals and angulars also were broken, but the aurals were 
undivided, Plate 2, Figures 3 and 5, On both Rhinochimaecra and Harriotta 
the line makes some descent backward from aural and cranial to orbital and 
thence proceeds nearly straight back to a point below the origin of the supra- 
caudal fin, where it turns toward the upper edge of the subeaudal fin and con- 
tinues along the lower edge of the side on the muscular portion to the end of 
the tail. The close general correspondence of the Iateral systems of these 
genera is very evident if the figures of Rhinochimaera pacifica, Plate 1, Fig- 
ure 1, and Plate 2, Figures 1 and 2, are placed side by side with those of 
Harriotta raleighana, Plate 2, Figures 3 to 5. 
