Jordan and Evermann. Fishes of North America. 2273 



837. RHOMBOCHIRUS, Gill. 



Rhombochirus, GILL, Proc. Ac. Nat. Sci. Pliila. 1863, 88 (osteochir). 



This genus agrees with Remora in every respect excepting the structure 

 of the pectoral tins. These are short and broad, rhombic in outline, the 

 rays all flat, broad and stiff, being partially ossified, although showing 

 the usual articulation ; upper rays of pectoral broader than the others. 

 One species known. (/J6jufio$, rhomb ; ^ez'p, hand.) 



2009. RHOMBOCHIRUS OSTEOCHIH (Cuvier). 



Head4f in length: disk 2; width between pectorals 5. D. XVIII-21 

 to 23 ; A. 20 or 21 ; P. 20. Mouth very small, maxillary not nearly reach- 

 ing to the line of the orbit ; outer series of teeth longer than the others. 

 Disk very large, broader and rougher than in Remora remora, extending 

 forward beyond the tip of the snout. Caudal fin emarginate, with rounded 

 angles. Light brown ; underside of head, ventral line, part of ventrals 

 and a spot on pectorals pale. West Indies north to Cape Cod; parasitic 

 on species of Tetrapturus ; rather rare, (odrsor, bone; #zp, hand.) 



Eeheneis osteochir, CUVIER, Ilegne Animal, Ed. 2, vol. n, 348, 1829, no locality given; 



GUNTHER, Cat., n, 381,1860; JORDAN & GILBERT, Synopsis, 418, 1883. 

 Eeheneis tetrapturorum, POEY, Memorias, n, 256, 1858, Cuba. (Coll. Poey.) 



Group TKACHINOIDEA. 

 (THE TRACHINOID FISHES.) 



A large group of transitional forms, some of them of doubtful relation- 

 ships, showing affinities with the Percoidea on the one hand and with the 

 Batrachoididcv and Blennoidea on the other. In general, the spinous dorsal is 

 short or weak, the soft dorsal long and similar to the anal, and the squama- 

 tion is less complete and less ctenoid than in the Percoidea. The skull is, in 

 general, depressed, with the supraocular crest low, and the suborbital stay 

 is wanting, although in some genera the suborbital bones are enlarged. 

 The bones of the skull are not strongly armed, and the ventral fins are 

 often inserted well forward, and they are sometimes reduced in size. 

 The group is divided by Dr. Gill into Percophidoidea, Trachinoidea, and 

 Uranoscopoidea. The two latter groups are natural and related, but, as 

 Dr. Gill observes, "the Percophidoidea are undoubtedly a heterogeneous 

 group and need a thorough revision." The relations of Bathy "master, Tricho- 

 don, and Latilus especially are uncertain. Several of the leading families 

 of this group are confined to the South Temperate Zone, and none of the 

 TracMnidcK occurs within our limits. 



a. Mouth horizontal or moderately oblique, the lips not fringed ; eyes lateral ; ventral 

 rays I, 5, their insertion more or less before the pectorals; suborbitals moderate; 

 gills 4, a slit behind the fourth. 



b. Snout subconic, not prolonged and spatulate; ventrals not widely separated, 

 c. Body covered with scales ; dorsal spines flexible. 



d. Lateral line complete; caudal fin forked ; vertebrae 24 to 27. 



MALACANTHID^S, cxo. 



