NATURAL SCIENCES OP PHILADELPHIA. 93 



Genus Liostomus Lacepede. 



Leiostomus Laclpbde Hist. Nat. vol. iv. p. 439. 

 Leiostomus Holhrooh, Southern Ichthyology, p. 21. 1847. 



Body subovate, compressed, highest under the first dorsal. Abdominal 

 outline less arched than the dorsal. 



Head short, with the fronto-occipital region very oblique, and the snout 

 high, subtruncated, and slightly convex. Eyes rather large, and mostly or 

 wholly anterior. Suborbital region high. 



Mouth small, scarcely oblique. Supramaxillars terminating under the 

 pupils, and mostly retractile under the suborbital's. 



Teeth in a villiform band in th3 upper jaw ; entirely absent in the lower. 



Preoperculum broadly rounded and entire, but with an apparently crenu- 

 lated membranous margin. Lateral and symphyseal pores present. 



Anterior dorsal fin sustained by ten spines. Anal with its second spine 

 short and weak. Caudal emarginated. 



The lower pharyngeal bones are furnished internally near their interno-pos- 

 terior margins with several rows of more or less truncated and excavated 

 molar teeth ; their other teeth are elongated and compressed, most slender 

 near their bases, curved with a sigmoid flexure. Their terminal portions 

 especially are of a burnt brown or blackish color. 



The posterior of the upper pharyngeal bones are also paved internally near 

 their ends with several rows of molars like those of the lower bones. The 

 rest of the posterior and the whole of the anterior pharyngeals are provided 

 with elongated, compressed teeth, most slender below, sigmoidally curved, 

 and with a constriction a short distance from the tip, which gives the apex an 

 unguiform aspect. 



The setse of the first pair of ceratohyals are furnished with nearly colorless 

 and very slender teeth ; the dentiferous laminae of the rest of the branchial 

 arches are compressed, and their margins armed with slender, deeply colored 

 teeth like those of the lower pharyngeal bones. 



The elongated teeth of the longer pharyngeals and the branchial arches 

 have some resemblance to the teeth of the pharyngeal bones of Cyprinoids, 

 called by Heckel raptatorial, ("dentes raptatorii ") but are much more slen- 

 der, especially at the base. ,, 



Type. Liostomus xanthurus Lac. 

 Syn. Leiostomus humeralis Cuv. et Vol. 

 Leiostomus obliquus Dekay. 



On the identity of the Genera NEOM.ENIS of Girard, and LTTTJANTJS of 



Bloch. 



BY THEODORE GILL. 



In the Ninth Annual Report of the Smithsonian Institution, a species of fish 

 has been described and referred to the genus Lobotes, under the name of Lo- 

 botes emarginatus. A few specimens of the species were taken in August, 

 among the grass along the banks of Egg Harbor river at Beesley's Point. 



Subsequently, Dr. Charles Girard, in his Report on the Ichthyology of the 

 United States and Mexican Boundary Survey, framed for the species a new- 

 genus, to which he gave the name of Neomamis, and which he referred to the 

 family of Msenidae. 



On an examination of the description and figures given in that Report, it 

 was evident that the species did not belong to either the families of Sciamoids 

 or Msenoids, as those groups have been characterized by Cuvier, and accepted 

 by almost all subsequent naturalists. It appeared to belong to the genus Me- 

 soprion, of the family of Percoids, but as no description was given of the ex- 

 1861.] 



