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 cranial at 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 

 anijular branch passes down and forwanl from the orbital to meet the nariah 

 but on Plagiostomia having the mouth backward from the eye the angular passes 

 backward. In tlie 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, Fioiure 1 , 

 the iusular meets the orbital, and the angular descends from the orbital and 



JO ' ~ 



passes downward and toward the front to meet the nasal and the oral : the 

 same is true in Ilarriotta, Plate 2, Figure 4. In Chimaera the oral meets the 

 ano-ular. Lat. Canal Svst., Plate II . Fiirures 3 and 4, but on Callorbvnrhus it 

 starts from the orbital. 1. c, Plates III. and IV., Fifrure 1. On both Rhinochi- 

 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 cranials 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 occipital 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, e.xcept the neural, Ijetween 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 an:iulars also were broken, but the aural? were 

 undivided, Plate 2, Figures 3 and 5. On both Rhinochimaera 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 subcaudal 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 lateral 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. 



