OCR Text |
Show 1903.] FISHES FROM RIO JANEIRO. 67 as in S. saliens, and the maxillary extends to below the posterior margin of the eye; the latter has a more slender body than any other species of this section, and the maxillary not reaching the posterior margin of the eye; like S. saliens, it occurs on both the Atlantic and Pacific coasts. A fifth species, S. nvundus Jordan &, Starks, from the Pacific Coast of Central America, is said to differ from S. alius in having a larger mouth; an example received from Dr. Jordan under this name has only four spines in the anterior dorsal, and is identical with S. saliens: it may be that the number of spines is variable in this species. SCOMBRID.E. American ichthyologists distinguish between Scombromorus regalis Bloch and S. macidatus Mitchill; but the supposed differences are so few, so trivial, and, judging by the few specimens I have been able to examine, so inconstant, that there can be but little doubt that the two are not distinct, and that the latter should be added to the synonymy of the former. American authors also agree in considering Cybium immaculatum Cuv. & Val. to be a synonym of Scombromorus cavalla Cuv. & Val. I am inclined to think, however, that two small examples in the British Museum Collection should be referred to S. immaculatus, and that they are specifically distinct from S. cavalla, two large examples of which are included in Dr. Goeldi's collection. The number of fin-rays is the same and the course of the lateral line similar in both species, and the differences will be apparent from the following short comparison :- SCOMBROMORUS CAVALLA CUV. & Val. Depth of body 5|-5| times in total length, length of head 4| times; depth of head (at level of upper angle of gill-opening) 1-8- times in its length, diameter of eye 6-6 g times. Gill-rakers nearly equal to ^ eye-diameter, 8 on lower part of anterior arch. Jaws with about 15 teeth on each side. Body dark above, silvery below, with traces of dark oval spots on the sides. Two specimens, 560 and 620 mm. in total length, from Rio Janeiro. SCOMBROMORUS IMMACULATUS CUV. & Val. Depth of body 34-4 times in total length, length of head 5 times; depth of head 1^- times in its length, diameter of eye 4|-44- times. Gill-rakers knob-like rudiments, 8-9 on lower part of anterior arch. Jaws with 8-10 teeth on each side. Body dark above, silvery on sides and below, without spots. Two specimens, 150 and 185 mm., from San Domingo. OPHIDIID.E. The genus Genypterus Philippi is distinguished from Lep-ophidium Gill by the stronger dentition, the outer series of teeth 5* |