FROGS OF SOUTHEASTERN BRAZIL — COCHRAN 241 



aeneus, shows little difference from an equal series of gaudichaudii. 

 The lighter color pattern mentioned by Muller demonstrates itself 

 only by the fact that the chevron-shaped interorbital mark is not 

 usually followed in aeneus by the )(-shaped dark marks on the anterior 

 part of the back. The hand spines do not number over 5 in any of 

 the 25 examples at hand. The maximum total length is 30 mm. 



The two foregoing species are grouped by the presence of a white 

 throat, usually without reticulations or spots except for a small one 

 in the center, as well as by the lack of a narrow, light dorsal Hne. 

 It is true that the presence or absence of a dorsal line is not generally 

 of much significance, as certain specimens may have it while others 

 lack it arbitrarily, but here it appears to have some value as a color 

 character, since the following forms, allied in other characters, usually 

 have a light dorsal line as well. 



The third form, trachystoma was first described by Reinhardt and 

 Liitken from Lag6a Santa, near BeUo Horizonte, in 1862, and was 

 redescribed as bresslaui from Morro Velho, also near BeUo Horizonte, 

 by Muller in 1924. This form has a reticulated throat, on which 

 nevertheless a median dark area is usually found. Its back is more 

 highly patterned than is that of the firet two species, since it has 

 usually a prominent dark bar extending diagonally inwards from be- 

 hind the eyes to the center of the back. The side of the head usually 

 has a distinct dark line. Not more than four spines occur on the hand. 



The fourth form, dispar, was described by Dr. Lutz in 1926. While 

 in many ways it closely resembles trachystoma, notably in having a 

 heavily reticulated throat, as well as in having a narrow hght dorso- 

 lateral hne, it differs shghtly in lacking the dark stripe on the side of 

 the head, and in having a greater degree of sexual dimorphism. 



For a statistical analysis of measurements of the species of Crosso- 

 dadylus here discussed, see pages 373 and 380. 



Key to the species of Crossodactylus of southeastern Brazil 



a.^ Throat usually white with no reticulations or spots except for a small one in 

 the center; no light middorsal line present, 

 b.i Hand spines up to 6; a pair of ) (-shaped dark marks on anterior part of 



back gaudichaudii (p. 248) 



6.* Hand spines up to 5; usually no ) (-shaped dorsal marks; a light narrow 



dorsolateral line present aeneus (p. 244) 



0.2 Throat reticulated (having a median dark area, however) ; a prominent dark 

 bar extending diagonally inwards from behind the eyes to center of back; 

 a light dorsal line; hand spines not more than 4. 

 6.* Side of head usually with a distinct dark line; hand spines up to 4. 



trachystoma (p. 252) 

 6.* No dark stripe on side of head; a greater degree of sexual dimorphism than 



in trachystoma: hand spines usually 3, rarely 4 dispar (p. 246) 



262006—55 17 



