150 ENGYSTOMATID 2. 
Habit slender ; tibio-tarsal articulation not 
reaching beyond the posterior corner of 
the eye; skin smooth...............- 5. varius, p. 152. 
Habit slender; tibio-tarsal articulation . 
marking the front of the orbit ........ 6. longirostris, p. 153. 
Habit slender; tibio-tarsal articulation 
marking the eye ; toes half webbed ; skin 
AVALLY «|. coin op nce ehen SU ener tate 9. cruciger, p. 154. 
Habit slender; tibio-tarsal articulation 
marking the eye; toes nearly entirely 
webbed; skin smooth; .y.0 222. g0e see 10. elegans, p. 155. 
Habit very slender ; tibio-tarsal articulation 
reaching beyond the eye; toes half 
webbed > skin smooth? 2... eeee se 11. bibroni, p. 155. 
II. First toe quite indistinct. 
Head as broad as long; yellow and brown 
BWOVE 47 ARR ie His ental ares wate aeae 7. flavescens, p. 153. 
Head a little longer than broad; black and 
BEEEN ADOVO: ©. a) ,c.00% « cones preeien ete 8. pulcher, p. 154. 
1. Phryniscus nigricans. ) 
Phryniscus nigricans, Giinth. Cat. p. 43. 
Phryniscus nigricans, Wiegm. Nov. Act. 1834, p. 264; Dum. § Bibr. 
p. 723; Bell, Zool. Beagle, p. 49, pl. 20. f. 8-5; D’Orbigny, Voy. 
Amér. mér., Rept. p. 11, pl. 15. £. 1-4; Espada, Viaj. Pacif., Vert. 
p11, pl. dot 9: 
Chaunus formosus, Tschudi, Batr. p. 87. 
? Phryniscus guttatus, Philippi, Arch. f. Naturg. 1861, p, 300. 
Habit stout. Head broader than long; snout short, rounded ; 
interorbital space broader than the upper eyelid. Fore limb shorter 
than the trunk; fingers short, first a little shorter than second ; 
metacarpal and subarticular tubercles well developed. Hind limb 
short, the tibio-tarsal articulation reaching hardly the shoulder ; 
toes short, one-third webbed, with prominent double subarticular 
tubercles ; two metatarsal tubercles. Upper surfaces covered with 
warts. Black, variously spotted with white. Male with a subgular 
vocal sac. 
Uruguay, Buenos Ayres. 
a-c. SQ. Maldonado. C. Darwin, Esq. [P.]. 
CBee vathe Monte Video. 
ea. Buenos Ayres. E. White [C. ]. 
en S. America. Sir A. Smith [| P.]. 
2. Phryniscus proboscideus. (Pate XIII. fig. 1.) 
Habit slender. Head as long as broad, its length contained twice 
and a half or twice and one fourth in the length of the trunk; 
snout much produced beyond the lip, truncate; loreal region con- 
cave; nostril near the tip of the snout; the diameter of the eye 
equals its distance from the nostril; interorbital space a little . 
