250 BARBOUR: ZOOGEOGRAPHY. 



and bowel meet; hind limb being extended along the side, heel almost reaches 

 eye; hind limbs being placed vertically to the axis of the body, the heels just 

 overlap, very slightly; skin above densely granular; a fairly well-defined glan- 

 dular ridge along back from snout to vent ; belly and hinder aspect of thighs 

 strongly glandular; throat, upper portion of chest, and anterior aspect of thighs 

 smooth; no differentiated adhesive disc area. 



The variation in color is very great, and may be gauged by the figures of the 

 typical specimens. Other variation is seen in the dorsal granulation, which is 

 always well developed, however, and in the fact that in the largest individuals 

 the heels barely meet posteriorly, when the limbs are laid vertically to the body. 

 The extreme adults, then, have very short limbs. 



The species belongs near E. auriculatus (Cope) from the Greater Antilles, 

 and E. martinicensis (Peters) from Guadeloupe, Martinique, St. Kitts, Jamaica, 

 and elsewhere. The latter species was, according to Stejneger (Rept. U. S. nat. 

 mus. for 1902, 1904, p. 584), introduced from Guadeloupe to Martinique; and 

 still more recently it has been carried to Jamaica (Barbour, Bull. M. C. Z., 

 1910, 52, p. 288). E. johnstonei can be separated from E. auriculatus Cope by 

 its vomerine teeth groups, which are less extended laterally, by its larger 

 tympanum, which is nearer the eye than in the other species, by its shorter 

 hind limbs, and the more considerable development of tubercles on back and 

 soles of feet. In E. martinicensis (Peters), the exposed tympanum is still less 

 in size. E. antillensis Reinhardt and Lutken, from St. Thomas, is easily 

 separable by its small feet. E. johnstonei grows to a larger size than any 

 specimen of E. martinicensis which I have been able to examine. The largest 

 Grenadian specimen is 32 mm. from snout to vent. Porto Rican examples 

 (E. auriculatus) reach a size of 43 mm., according to Stejneger, and there are 

 several of almost this size in the collection here. 



In the Zoologist (1889, p. 298), Col. Fielden of Barbados makes the follow- 

 ing note regarding what he calls Hylodes martinicensis: — 



"The little Tree-frog Hylodes martinicensis, Tschudi, is undoubtedly a very 

 recent introduction; twenty years ago, as I am credibly informed, it was quite 

 unknown. It is now spread over the entire island. ..." 



This is substantiated by Bellin, who wrote in 1758, in his Description geo- 

 graphique des Isles Antilles possedes par les Anglais (Paris, 1758, p. 61), that 

 upon the island of Barbados "II n'y a ni Crapauds ni Grenouilles." 



This species is named for His Honor Robert S. Johnstone, Chief Justice 

 of Grenada and the Grenadines, who very kindly aided the members of the 

 Museum's expedition while at Grenada. 



