ICHTHYOLOGY OF THE LESSER ANTILLES. 



457 





1. Doraiil I'm of branched radii ; no second door of brain case ; transverse wing on inside of hyomandibularj 

 second superior pharyngeal rod-like, first present, third simple. Oplieocephalida. 



2. Dorsal liii of spinous and soft, portion ; no hyomandibnlar wing ; second superior pharyngeal subconic, third 

 vci'v large of two horizontal lamina!, the superior supported by the inferior by a vertical rod. Superior branchihyals, 

 second a, triangular plate with supero-exterior process ; third and fourth tri-radiate. Mugilidoi. 



8. Dorsal fm of spinous and soft portions, ventrals more abdominal; third superior pharyngeal long and wide, 

 simple, second rod-like. Basis cranii with upper floor better developed anteriorly. Atherinidai. 



The family of Gyprinodontidm approaches the Oplieoceplialidm very closely, differing as to ordinal characters, in 

 the presence of the ductus pneumaticus. The form of the maxillary bone and anterior position of the ventral fins 

 ally them to the Mugilidce, while the enlarged third superior pharyngeal even exceeds that of the Atherinida. The 

 physiognomy brings it into relation with this order. 



Symkntoonatiij Mouth bounded by the premaxillary only; parietal bone very much reduced ; posttemporal 

 slender, furoate ; supraclaviole not distinct. Peotoral fln with elevated basis ; no interolaviole. Superior pharyngeals 

 second and third large, oval, not articulated fo cranium, sending processes forward; fourth wanting. Inferior pha- 

 ryngeals ooossifled. Basis cranii double in front, but without muscular tube. 



The only family of this order, the SaomberesocidcB, lias a diphycercal tail, and no spinous dorsal I'm. In its rather 

 weak superior branchihyals it shows resemblance to the next order. 



Hbmibranchii. Mouth bounded above by premaxillary only ; posttemporal not furcate. Pectoral fins elevated ! 

 interolavicles developed. Superior pharyngeals small, weak ; second, third, and generally fourth present; superior 

 branchihyals rudimental, the fourth, and sometimes others, wanting. Inferior pharyngeals distinct. Branchial pro- 

 cesses narrow lamina!. Basis cranii simple, no tube. 



1. Anterior vertebras but little enlarged ; dorsal spines strong ; first, second and third superior branchihyals and 

 second and third superior pharyngeals present, Gasterosteidm, 



2. Four anterior dorsal vertebrae much elongate (centrum and spine united by suturo in Fistularia), dorsal spines 

 very weak, or none. 



a. Superior branchihyals oartilage, three superior pharyngeals. 



(j Throe anterior superior branchihyals osseous, three superior pharyngeals, directed forwards. 



',',. Pour anterior vertebra much elongate, with strong diapophyses, and normal articulations. 



Fourth superior branchihyal and first and fourth superior pharyngeals only wanting. 



4. Six anterior vertebra! extremely elongate, with normal articulations of centra. 



Fourth superior branchihyal and all the superior pharyngeals wanting. 



This very natural order connects the ordinary fishes immediately with the LophobraneJiii. The family Oat- 

 terosteidCB is the least specialized of them, and presents some relationship to Nematocentris, a genus of AtTierinidm, 

 from Australia. The latter lias Hat, transverse! ami senate spinous rays to both dorsal tins, which both exhibit soft 

 rays, as though in anticipation of their absence anteriorly in Oasterosteui. The relationships of this order to the 

 Lophobranchs are numerous. They are, the weakening of the branchial apparatus, the presence of the interolavicles 

 (which I find in all), the simplicity of the posttemporal bone and basis cranii, the shortness of the branchial processes 

 the prolongation of the muzzle and the ganoid plates, are characters of subordinate relationship. On the part of the 

 Lophobranchii, the BoUnostomidm approach this order, but to which family I am not sure, probably to the Fis- 

 tulariidm. 



LOPHOBRANCHII. Mouth bounded by the premaxillary above; posttemporal simple, cooossilicd with the cra- 

 nium. Basis cranii simple. Pectoral fins with elevated basis ; well developed interolavicles. Anterior vertebra 

 modified, the diapophyses much expanded. Inferior and superior pharyngeals and superior branchihyals wanting or 

 unossilicd. Branchial processes in tuftS*. 



1. A. weak spinous dorsal fln. Solenostomidcs. 



2. No spinous dorsal fin. 



AMERI. PHILOSO. 800. — VOL. XIV. — I 1 :> 



Fistulariidm. 



AuloHtom.it. 



Fistularia. 

 Centrist- iil,e, 

 Amphisilida. 



( SyngnatMdce. 

 \ Hippoeampidce. 



