Fishes of the Order Cyprinodontes 



19 



The name taeniatus was proposed by Regan, as a "variety," to distinguish 

 a form from San Domingo de Guzman, southern Mexico, the distinctive fea- 

 tures as pointed out being the development of a median longitudinal sitripe 

 and a higher number of dorsal rays. Since the color feature will probably 

 prove to be only a phase without geographical significance, and since the high 

 number of rays appears to be a general characteristic of the southern form of 

 the species, it is here proposed to use the name taeniatus for that subspecies. 



The range of taeniatus may then be extended to cover the Atlantic drain- 

 age of the Isthmus of Tehuantepec, Guatemala and British Honduras. 



Frequency table. — Number of dorsal rays in Pseudoxiphophorus bimaculatus 



laoiiatiis: 



Locality Authority 14 15 16 // 



Sanborn, Mexico 

 Rio Tonto, Mexico 

 San Domingo de Guzman, Mexico 

 San Domingo de Guzman, Mexico 

 Belize, British Honduras 



Authority 14 



Hubbs I 



Regan (1905) 5 



Regan (190S) 



Regan (in lit.) i 



Hubbs 



-Dorsal rays- 

 15 16 



2 



7 3 



I 



2 I 



I 



III 

 Priapichthys annectens Regan 



This species as here construed includes two subspecies : typical annectens, 

 of the lowland streams on the Atlantic slope of Costa Rica, and the new sub- 

 species hesperis, inhabiting the headwaters of the Rio Grande de Tarcoles, a 

 Pacific stream. The form hesperis, when compared alone with typical an- 

 nectens, appears to represent a distinct species, but the differences between 

 the two forms are found to be bridged over when one determines the charac- 

 ters of series from Rio Reventazon. which flows down the east.slope of Costa 

 Rica opposite these headwaters of the Tarcoles. The connection between 

 the two forms is not by an even areal intergradation, but rather by what may 

 be termed mosaic intergradation. 



Excluding for the present the intermediate races of the Reventazon basin, 

 the differences between the two sul)species of Priapichthys annectens may be 

 expressed as follows : 



Character annectens Intermediate races hesperis 



Head in length, in adult female.... 3.5 to 3.75 3.6 to 4.2, 3.8 to 4.35 



rarely to 4.5 



Eye in head 3.0 to 3.7 2.9 to 3.75 3.6 to 4.3 



Mouth usually various usually wider 



narrower 

 Pigment of margins of scale pockets, tending to various less con- 

 form spots centrated 



Finally, the dorsal rays are reduced in number in the subspecies hesperis, 

 as is indicated in the following tabulation : 



Frequency table. — Number of dorsal rays in the tzuo subspecies af Priapichthys 

 annectens: 



Dorsal rays 



8 p 10 II Average 



P. a. annectens . . 22 6 10.21 



Intermediate races i 54 28 i 9.34 



P. a. hesperis 3 79 18 . . 9.15 



