10 General Account of the Ithacan Anura. 



ever, it was Rana-like. Again, at the height of pairing, differences can 

 readily be discovered in the same species; e. g., in Hyla pickeringii and 

 Bufo I. americanus both axillary and supra-axillary types occur. 



Male frogs embrace the head of a carp,* bowfin, or any other fish 

 because the normal pectoral and lumbar regions are too large; the 

 head is the only region they can possibly span, and the eyes the only 

 place into which they can dig the hands. The same was true of the 

 peepers and swamp cricket-frogs when embracing Ambystoma. The 

 head was a favorite region, as many as three being on it at once. When 

 a female Rana or Bufo is in possession of a male embracing normally, 

 the head region is the part most frequently seized by the supernumerary 

 males. Sometimes, in such instances, a male will seize the head and 

 hold the female from the ventral side, apposing his venter to that of the 

 female, she then being in the possession of two males. Or a male may 

 rest on the top of the male in possession, holding the female by the head. 



There are a few records of lumbar embraces with four different 

 species, typically axillary; apparently such records are explained by 

 the weakening due partly to captivity and partly to previous fruitful 

 mating and insemination. A male Rana pipiens so embraced for three 

 hours and retained its hold, though roughly handled. In the field 

 one record of lumbar amplexation was found with Bufo I. americanus. 

 A weakened Chorophilus usually held to its axillary fashion, but often 

 could not or did not maintain it ; several times it slipped back to axillo- 

 inguinal, inguinal, and lumbar modes, but never kept them perma- 

 nently. In another instance three pairs of toads laid, broke, and then 

 the males resumed the embraces; this they did for six days and the 

 amplexation was lumbar or midway between lumbar and axillary. 



It would seem that the lumbar form of approach is the least vigorous 

 and the pectoral the hardest to break. Some examples of Rana, when 

 weakened, slip to the lumbar embrace, although not so readily as 

 species with the axillary form of embrace; and it is extremely difficult 

 to transfer these lumbar Rana pairs to photographic stands or jars, 

 an operation easily done for typical pectoral pairs and quite easily 

 accomplished with typical axillary ones. When males of the genus 

 Rana are brought into captivity before the normal breeding season for 

 their species they sometimes feebly grasp a female in a lumbar fashion ; 

 e. g., a male Rana clamata so held a female May 15, 1913 (two weeks or 

 more preceding the beginning of egg-laying in the field). Then, too, in 

 the Pelobatida?, where it is supposedly the normal rule (so recorded for 

 European forms), the various species, when handled, break more easily 

 than do those of the genus Rana, and this was our experience with a cap- 

 tive mating lumbar pair of Scaphiopus holbrooki, which so amplexated 

 several times, but quickly released if receiving much attention. 



*For a resume of such phenomena see Dr. T. N. Gill's "The Family of Cyprinids and 

 the Carp as its Type," Smithsonian Misc. Colls, vol. XLVIII, 1907, pp. 208, 209. 



