Introduction. xxxv 



the Rio Panuco. I visited the tributaries of this river where they are 

 crossed by the railroad. 



At Garza Valdez most of the river bed was dry, the water being 

 confined to deep holes. The bed of the stream was covered with large 

 waterworn rocks, indicating a rapid current during the wet season. 

 Along the banks were many large cedar trees. 



The tributary at La Cruz contained at the time of my visit a con- 

 siderable amount of clear, swiftly running water. This is the largest 

 river between Tampico and Monterey, and it no doubt contains many 

 more fishes than any other of the streams in this region. Big large- 

 mouthed black bass, catfish, trucha, cichlids, and suckers could be 

 seen in abundance from the bank. 



At Santa Engracia there was but little running water in the river. 

 Above a dam near the railroad bridge the water in the channel was 

 in many places over six feet deep and very clear. This stream also 

 contained many large-mouthed black bass, a few of which I captured. 

 So far as known this is the southern limit of this species. Along the 

 banks of the stream are also many large cedar trees. The trucha, 

 or trout of the natives, was also abundant, but I was unable to capture 

 any of them. 



The stream at Victoria is small, and I found but little water in it. 

 Of the eighteen species known from this river system, twelve* are 

 northern forms and six are tropical. 



*Ichthyaelurus furcatus (Le Sueur) : Rio Soto la Marina. 



*Amiurus lupus (Girard) : Garza Valdez; La Cruz. 



*Carpiodes tumidus Baird & Girard: Garza Valdez. 



*Carpiodes elongatus Meek: La Cruz. 



*Myzostoma congestum (Baird & Girard) : Garza Valdez; Victoria. 



*Nototropis braytoni (Jordan & Evermann) : Garza Valdez; La Cruz; Santa En- 

 gracia; Victoria. 



Tetragonopterus mexicanus Filippi: Garza Valdez; La Cruz; Santa Engracia; 

 Victoria. 



*Anguilla chrysypa Rafinesque: La Cruz. 



*Fundulus similis (Baird& Girard): Victoria. 



*Gambusia affinis (Baird & Girard): Garza Valdez; La Cruz; Santa Engracia. 



Platypoecilus variatus Meek: Garza Valdez; Santa Engracia; Victoria. 



Poecilia sphenops Cuvier & Valenciennes: Garza Valdez; La Cruz; Santa En- 

 gracia; Victoria. 



*Mollienesia latipinna Le Sueur: La Vega. 



*Micropterus salmonoides (Lacep6de) : La Cruz; Santa Engracia. 



*Haploidonotus grunniens Rafinesque: La Cruz. 



Cichlasoma cyanoguttatum (Baird & Girard): La Cruz; Garza Valdez; Santa 

 Engrafcia; Victoria. 



Neetroplus carpintis Jordan & Snyder: Garza Valdez; La Cruz; Santa Engracia; 

 Victoria. 



Philypnus dormitor (Lacepede) : Santa Engracia; La Vega. 



