THE DIFFERENTIAL CHARACTERS OF THE SYNGNATHID 

 AND HIPPOCAMPID FISHES. 



By Theodore Gill, LL. D. 



The typical Lophobranchs have been distributed among two fami- 

 lies by several authors, but by most have been combined in one. The 

 reasons generally given for the separation have not been very satis- 

 factory, and I now propose to indicate those which have influenced me. 



The first to recognize the family difference between the groups in 

 question, and to give appropriate names to them, was Prof. Giovanni 

 D. Nardo. 



In 1842 (1844)' Professor Nardo divided the Lophobranchs into two 

 families, Syngnathidse and Hippocampidse, in the following terms : 



Fam. 1. Syngnathidce Nardo. Annuli protovertebrales constituiintur sciitia squa- 

 moso-corneis, medio angulosis, symmetrice striatis, contiguis, subimbricatis, corio 

 superpositis, adhserentissimis. Ossa nasalia et palatina usque ad apicem rostri pro- 

 tracta, efc maxillae superiori coujuncta. Epidermis crassa, atipata, continua, adhiB- 

 rens, scutorum strias exhibens. Appendices cutanese nullse. 



Subfamilial, SyngnatMni Nardo. Ventrales uullse ; os terminale ; apertura bran- 

 chiarum ad nucham. 



Subfamilia 2. ScypMni Nardo.^ Corpus pinna unica sen dorsali instructum est. 



Fam. 2. Hippocamindoc Nardo. Annuli protovertebrales constituuntur ossiculis 

 quadraugularibus, angulis porrectis, centre in tuberculum salientibus, distautes, et 

 sibi invicem i)er angulos tantum seriatim et symmetrice conjunctis, corio intriu- 

 secus obsitis. Ossa nasalia et palatina ad medium tantum rostri protracta, et maxillie 

 superiori contigua. Epidermis continua, adhaireutissima, glabra. Appendices 

 cutana^ multae, etc. 



Subfamilial. Hippocampini Nardo. Ventrales et caudales nuUas; os terminale; 

 aperturu brancbiarum ad nucham ec. 



Subfamilia 2. regasini Nardo. Ventrales iiliformes ; os iuferum ad basin rostri ; 

 apertura branchiarum ante pinuas pectorales, etc. 



Subfamilia 3. Solenostomini Nardo. Ventrales grandes, pectoralibus conjunctse; 

 08 terminale ; apertura branchiarum ad jugulum ec. 



'Cousiderazione sopre alcune nuove famiglie de' Syngnatbi e de' Plectognathi, e 

 Bui caratteri auatomici che le distinguono. <Atti Scienz. Ital., 1843, pp. 244, 245. 



■Syiifinathini, Bonaparte, Catal. Metod. Pesci Europei, pp. 9, 89, 1846, is appar- 

 ently coecjual with ScypMni of Nardo. 



Proceedings of the United States National Museum, Vol. XVIII— No. 1049. 



153 



