^°189i!'''] PROCEEDINGS OF THE NATIONAL MUSEUM, 397 



Certainly there are no two closely related genera of Labricls that are 

 differentiated from each other by more numerous characters than thus 

 become apparent between Labrichthys and Pseudolabrus. Direct com- 

 parison of specimens of the two genera would doubtless reveal others. 

 Especially significant are the differences in the contour of the head and 

 the relative proportions of the opercular api)aratus, for they doubtless 

 indicate decided osteological deviations. Far more important are the 

 discrepancies between the two than such as exist between iSeinicossy- 

 phus, Trochocopus, Decodon, Pteragogus, and Cossyphus, for those genera 

 are very closely related, and the cranial differences between most of 

 them * are unimportant. The differences in the hy popharyngeal appear 

 to be so great that Bleeker was probably justified in referring them to 

 different subfamilies. 



On the one hand, the hypopharyngeal of the Labrichthyinae seems 

 indeed to be anomalous, judging by the illustration of that of Diproc- 

 tacanthus xantlmrus. This is represented as linear and almost semicir- 

 cular, destitute of an anterior shaft and with the short row of teeth 

 confined to the convex median portion. So divergent is such a form 

 from that exemplified by Labrids generally that corroboration of the 

 figure is much needed, as well as explanation how the bone is connected 

 with the preceding branchial arch. 



On the other hand, the hypopharyngeal of Pseudolabrtis is quite 

 typical ; it has the usual long compressed anterior shaft and moder- 

 ately wide surface studded with teeth; in fact, it is essentially similar 

 to that of the typical Cossyphiformes and Pseudolabriformes. 



The lips of Pseudolabrus are probably even much more different from 

 those of Labrichthys than appears from the notices by Bleeker and by 

 Kuer and Steindach uer of those of the latter.t 



The structure of the lips indeed furnishes excellent data for diag- 

 nosis of many genera of Labrids. Pseudolabrus differs much from the 

 typical Cossyyphiformes in its lower lip. The upper lip is everted and 

 obliquely multiplicate, and the inner plicfe are villous at their margins. 

 The lower lip is double, the outer being everted and developed as plain 

 lobes on each side, widely separated at the chin, while the inner is erect 

 and has a villous margin, which is free from the jaw as well as from the 

 outer lip all around. 



IV. 



I have thus far discussed the questions at issue on the assumption 

 that any further complications of the subject were unknown, and this 

 assumption is iirobably not illegitimate, so far as most authors who 

 have treated of the fishes under consideration is concerned. Indeed, 



* I have not been able to examine the crania of Semicossyphus and Pteragogus. 



t Labrichthys cyanotajnia has lips thus discribed by Bleeker (Atlas Ich. Ind. Ned., 

 I, 154,): — "labiis latis carnosis, inferiore bilobo lobis fimbriatis," The diagnosis of 

 Kner and Steindachner has been given on a previous page. 



