NATURAL SCIENCES OP PHILADELPHIA. 129 



The ventrals are on the skies of the breast, and their bases are parallel or 

 nearly so with the fish's length : they are separated from each other by a very 

 wide and flattened area, and their posterior rays are connected by a membrane 

 to the lower half of the bases of the pectoral fins. These fins are more or less 

 larger than the pectorals. 



Such are the chief external characters of this singular group, and as they 

 are apparently common to all its species, they should in this case be elimi- 

 nated from the generic, and much more from the specific description. The 

 different proportions of these parts are their relative situation to each other, 

 are alone specific characters. The fins present a singular diversity, not alone 

 in form, but in structure, in even the same species. Some of them, especially 

 the first dorsal and caudal, are often much more developed in the males than 

 in the females. The rays, at least of many of them, are very variable in their 

 character, sometimes nearly all them being simple, and at others, almost all 

 are branched. It is therefore impossible to now give a formula indicative of 

 the exact permanent condition of the fins. 



Two of the genera confounded under the name of Callionymus, as has been 

 already stated, differ chiefly in the position of the branchial apertures. In the 

 true Callionymi, they are of an oval form, and situated near the inner angle of 

 the superior opercular margin, and on the sides of the nape. In another group, 

 they are present as small perpendicular slits behind the opercular margin, and 

 have been well described by Valenciennes in the article on Callionymus oper- 

 cularis. They are by that naturalist said to be concealed by a long pointed 

 production of the operculum, and by a membrane which connects this produc- 

 tion to the nape, and they thus present the appearance of transverse slits 

 under this membrane when the opercula arc raised up. Valenciennes has well 

 remarked that the species whose peculiarity he thus describes may one day 

 become the type of a peculiar sub-genus, but he has not so named it. There 

 can be at this day no doubt entertained as to the propriety of forming for the 

 species thus distinguished a distinct genus, and the name of Synchiropus is 

 offered as its generic appellation, a name which alludes to the peculiar con- 

 nection of the ventrals to the bases of the pectorals. The genus that will be 

 described under this name does not embrace the Callionymus dactylopus of 

 Bennet which is the type of a distinct, but allied genus. 



The generic diagnoses of the genera will then be as follows : 



I. Callionymus, L. restr. 



Aperturae branchiales ovataa, in latere nuchae utroque sitae. Pinnae ven- 

 trales spina et quinque radiis ramosis, omnibus membrana conjunctis. 



This genus, as far as relates to the species referred to it, is synonymous 

 with the genus Uranoscopus of Gronovius, who has reversed the Linnaean names 

 of Callionymus and Uranoscopus, as used by modern naturalists, the former 

 Gronovian genus including the Uranoscopi and the latter the Callionymi. 



Besides the numerous species that have been already described, two that 

 appear to be undescribed are in the collection of the North Pacific Exploring 

 Expedition. One (C. taniatus Gill,) is lilac colored, with a silvery line and 

 row of spots on the sides, and with a black spot, bordered by white, on the 

 first dorsal. The other (C. inframundus Gill,) is light brownish, marbled 

 with white, and with a blackish first dorsal. The former is from China ; the 

 latter from Japan. 



II. Synchiropus, Gill. 



Aperturae branchiales parvae, lineares, fere perpendiculares, post opercula. 

 Pinnae ventrales radiis spinoso et quinque ramosis membrana conjunctis. 



The genus thus characterized embraces five known species, which are all 

 inhabitants of the Eastern seas; 



1. S. lateralis . 



Syn. Callionymus lateralis, Richardson, Zoology Sulphur, p. 65, pi. xxxvii, 

 figs. 5 and 6. 1844. 



1859.] 



