42 BULLETIN 150, UNITED STATES NATIONAL MUSEUM 



ACANTH0UPAEI8 



AcanthoUparis differs widely from any known genus, and its 

 origin is in doubt. It differs from Paraliparis in the absence of 

 pyloric coeca and the projection of the opercular arms from the side 

 of the head as spines. The only character which AcanthoUparis 

 shares with Paraliparis and not with Careproctus is the loss of the 

 disk. It appears most likely that AcanthoUparis has been derived 

 from the Paraliparis stem. 



NECT0LIPARI3 8 



NectoUparis differs widely from all the other genera in having 

 only five branchiostegals, the gill slit restricted to the front of the 

 pectoral, and the vent situated on the throat and opening forward.^ 

 The absence of the disk suggests that the genus may have been de- 

 rived from Paraliparis. The single series of teeth in N. pelagicus 

 resembles the condition found in P. copei and related species. 



In this discussion it has been assumed that the trilobed teeth and 

 dorsal notch wherever found are primitive and not secondarily 

 acquired and that the loss of the posterior nostril has taken place 

 along only one line of development and indicates genetic relationships. 



KEY TO GENERA 



A*. Nostril double; pseudobrauchiae present; pectoral typically with more rays 

 than anal. 



B'. Pyloric coeca less than 150, probably always less than 100 Liparis. 



B*. Pyloric coeca more than 150, probably always more than 200 Polypera. 



A*. Nostril single; pseudobranchiae apparently always absent; coloration not 

 variegated; pectoral typically with less rays than anal. 

 C*. Dorsal notched. 



D >. Coeca present Temnocara. 



C Dorsal unnotched, or if notched the pupil round. 

 E'. Disk present. 

 F'. Disk perfect. 



G ^ Snout without barbels. 

 H •. Gill slit well developed. 



J'. Pupil round or but slightly oval; no color blotches on the 



body Careproctus. 



J'. Pupil reduced to a horizontal slit; body with large round- 

 ish or irregular blotches Crystallichthys. 



H*. Gill slit reduced to a pore Gyrinichthys. 



G*. Barbels present on the snout Crystallias. 



F^. Disk rudimentary, the rays absent Elassodiscus. 



» In a recent article Johnsen (1919) questions the validity of this genus. We are unable to agree with 

 his opinion. 



' A new genus, Lipariscus, has been described since the above was written. Its relationships with 

 NectoUparis will be found discussed in the appendix on page 194. 



