16 UH. S. .1. BOLKAY; DESCRIPTIOX OF A HYBHIU OF KANA ESCfLENTA L. ANU HAXA RIUIBUXUA FALL. 
As regards the colouring of this hybrid specimen il approaches Ihat of R. ridi- 
bunda, inasmuch as llie dark spols on the back are very large, and edged by a 
greyish white border. 
The dark marbling of the hind part of the limbs was filled — on the living 
specimen — by a soiled white colour. 
Tinally it is worth remarking that the whole belly is covered with large smokc 
grey spots which are, as is well known mostly characteristic of the typical Rana 
ridibimda Pall. 
Dimensions in mm. 
Froni snoiit to vent . 75 Diameter of tympannm .... 5’5 
Lengthofhead . 23 Fore limb .38 
Width of head . 2fi Hind limb .115 
Diameter of eye . 8 Tibia .35 
Interorbilal width . 3-5 Foot .39 
From eye to nostril . 5 Inner loe (from tubercle) ... 9 
From eve to end of snoiit . . . 11 Inner metatarsal tubercle ... 4 
Sirailar bybrids have been long known in the literature, without any positive 
expression as to their hybrid nature. This is however clearly expressed by ^^’oLTERS- 
TOHFF in the remarks^ he wrote about an article of mine and in which he says 
that formerly when meeting with a frog bearing mixed characters he was 
never sure whether be ought to consider it as a hybrid or as some connec- 
ting form. 
In one of bis earlier articles ^ Woltehstouff has already described a dubious 
Fdible Frog with long tibias but with enormous inner metatarsal tubercle, which 
accordiug to hini most probably is a hybrid of R. esc. rid. and R. esc. typ. 
Lessonae. 
In the same article he also mentions a R. esculenta from the Lake of Sadworn, 
with comparatively weakly developed inner metatarsal tubercle, but having a bright 
yellow colour on the hind part of the thigs, and which — as he says — probably 
is a hybrid between R. esc. typ. and R. rid. 
He remarks in parenthesis, having found no R. ridibimda in that part of the 
country. 
To-day however, Woltehstorff is also of the opinion^ that these frogs are 
bybrids. 
Artiticially bred hybrid frogs are known in the literature. 
Professor L. v. Mehely has described bybrids of Boiubinator igneiis Laur. 
and B. pachypiis Bonap. which originated in the natural way, in the open air.^ 
I wished to contribute by this small article to the statements already published 
about the frog bybrids originated in the natural way. 
‘ Woltcrstorff W., Bemerkungen zu Bolkay : Über die Artl)ercchtigung des Flusst'roschc.s. 
«Laccrta» Nr. 11, «Wochenschril'l», V. Jahrg., 1908. 
^ WolterstorlT, .Schritten d. Natuilbrsch. Ges. in Danzig, N. F. XI. 1904, p. 50. 
’ WolterstorlT W., Bemerkungen zu Bolka}'^: Über die Artljereclitigung des Flussfrosches. 
«Lacerta» Nr. 14, «Wochenschrift», V. Jahrg., 1908. 
* Mehely Lajos: A Mecsekhegyseg es a Kapcla herpelologiai'Viszonyai. .-Ulattani Közleme- 
nyek, III. 1901, p. 244. (Also in Ihe German language: Die herpetologischen Verhältnisse ites 
Meesek-Gebirges und der Kapela. Ann. Mus. Nal. Ilung., III. 1905. p. 259.). 
