282 PROCEEDINGS OF THE ACADEMY OF 1883.] 



2. Arius caerulescens GUnther. 



(Cat. Fish. Brit. Mus., v, 149.) 



Types from Huamuchal, Pacific slope. 



Head more depressed than in A. assimilis. Fontanelle A^ery 

 short, ending abruptly behind and not produced in a groove 

 behind the smooth area of the top of the head, the boundary of 

 the smooth area being rather broadly convex. Occipital process 

 broader than long, its edges nearl}^ straight. Bands of palatine 

 teeth small, not produced backward on the inner margin. Paired 

 fins black at base above. This species is allied to A. guntemal- 

 ensis, but is apparently distinct. It is well separated from A. 

 assimilis. 



3. Arius seemanni GUnther. 



' (Cat. Fish. Brit. Mus., v, 147.) 

 {? Arius assimilis, Jor. & Gilb., Bull. U. S. Fish Com., 1882, 47.) 



Type from Central America, the exact locality unknown. 



Fontanelle extending backward in a deep and narrow groove, 

 which reaches the occipital process. Middle of top of head 

 smooth, much as in A. plalypogon. 



It is probable that this specimen belongs to the species hereto- 

 fore erroneous!}" called by us Ariui^ assimilis. We have had some 

 hesitation in making this identification, because in none of our 

 Mazatlan specimens does the fontanelle reach the occipital pro- 

 cess, and it is not certain that the type of A. aeemanni came 

 from the Pacific coast. Still, the probability is so strongly in 

 favor of identity that, in absence of further evidence, we shall 

 consider them the same. 



4. Myrophis punctatus Lli ken. * 



(Vidensk. Meddel. Nat. Foreu., Kjob, 1«51, 1 .) 



Type, West Indies ; Suenson Coll. 



Beginning of dorsal midway between gill-opening and vent. 

 Head 2f in trunk. Cleft of mouth about 3^ in head. This is 

 apparently identical with M. microsligmins Poey (Rep. Fis. Nat., 

 ii, 50). The description of M. punctatus Gthr. (viii, 51 ) is taken 

 from the Panama species, M. vafer Jor. & Gilb. It is bareh' 

 possible that M. lumbricus Jor. & Gilb. will prove to be the 

 young of M. punctatus. 



