1895. ' PROCEEDINGS OF THE NATIONAL MUSEUM. 155 



2. Family. — Sea-horses (Hippocampidie). — Head and body com- 

 pressed ; snout narrow, tubular ; mouth terminal ; jiectorals small, dor- 

 sal single; caudal fin wanting. 



3. Family. — Winged Sea-horses (Pegasidae). 



Mr. Adams' work was largely based on Swainson's, and his diag- 

 noses of families were often essentially similar to many of Swainson's. 



In 1858 Dr. Girard adopted the ftimilies Hippocampidfe (after Owen 

 and Baird) and Syngnathidre, with the following data: 



Family HIPPOCAMPID^, Owen. 



The sea-horse family being composed, to onr knowledge, of but one genus {Hippo- 

 campus), we will not enlarge upon its characters here, since alluding to them would 

 be a mere repetition of their enumeration further on. 



He added that — 



The position these fishes assume in the media in which tliey live is not the least of 

 their peculiarities entitling them to the rank of a family in the ichthyic method. 



Family SYXGNATHID/E, Bonaparte. 



The same remark consigned under the head of Hippocampida?- applies again to 

 this family, for the genus Syngnathus is the sole generic type which we have had an 

 opportunity of examining. Those established by Kaup are quite numeroiis, but the 

 descrii)tion of their characters has not yet come into our hands. 



The characters thus connected indirectly with the families in (ques- 

 tion are simply of generic value, and the agreement in many characters 

 of Hippocampus with G aster otoheus, Solenognathus and Phijllopteryx, 

 associated with it by Kaup, shows that the "position these fishes as- 

 sume" is of minor value and not significant of family differentiation. 

 As Girard had knowledge of Kaup's article published in 1853,' he had 

 data to forbid the assumptions he indulged in. 



In 1882 Jordan and Gilbert accepted the two families in question 

 and briefly differentiated them as follows: 



" E. Snout tubular, bearing the short, toothless mouth at its end; body mailed. 

 " F. Caudal lin present; head in the line of the axis of the hody . . Siingnathidce. 

 "FF. Caudal fin wanting; head not in line of axis of body.. . Hippocampidw." 



In the descriptive portion of their synopsis they gave amplified 

 descrii)tions of the families, but did not add to their differential 

 characters. 



TI. 



It will be obvious to anyone who compares the definitions above 

 given with a collection of the fishes for which thej^ were framed, that 

 they are not applicable to any natural groups, and that such natural 

 groups are definable by characters that have been generally neglected. 

 I am therefore led to submit diagnoses of the several groups which 

 appear to me to be at least better than those fot which they are 



lUebersicht der Lophobranchier. <Archiv Naturg., 1853, I, 226-234. 



