1887.] . J---"- [Claj'pole. 



snake (Ophibohis tnangulus) of which the remainder ot the body appears 

 to be perfectly normal. Another case is recorded by Prof. Wyman * of a 

 water snake (Tropidonotus sipedon) with two heads and two tails, and a 

 similar case as well as one of a five-legged frog is reported by Mr. Kings- 

 ley.f Mr. Ryder also calls attention:): to a specimen of the pickerel frog 

 (Bana palustris) with five limbs or rather an additional pair of hind 

 limbs fused together. This leg had six toes and its digital formula might 

 be written— 5, 4, 3, 3, 4, 5. 



Among insects such monstrous forms have been observed. " Numerous 

 instances of supernumerary legs and antennte are recorded. The antennte 

 are sometimes double but more Sbmmonly the legs." Asmuss has col- 

 lected eight examples and in six of these the parts on one side are treble. 

 "Newport relates that from a single coxa of Scarites pyrachmon on the left 

 side two trochanters originated. The anterior supported the true protho- 

 racic leg, while the posterior carried two legs each as well formed as the 

 first. "§ 



"Other deformities occur in the wings. Cases of hermaphroditism are 

 on record in which one wing bears the colors of the male insect and the 

 other those of the female. Sometimes the wings are aborted or deformed." 



Most persons who have had much experience in the breeding of animals 

 can recall similar instances. 



At a recent meeting of the American Entomological Society a mon- 

 strosity was noted in a longicorn beetle of the genus Acmceops in which 

 the left front leg has three tarsi. A specimen in the collection of Prof. 

 Riley {Isosoma tritici) was also described in which the fore wings are rep- 

 resented by rudimentary pads while the hind wings are fully developed 

 (Science, Dec. 5, 1884, p. v). 



Mr. J. A. Ryder has recenily recorded similar malformation among 

 lobsters under his observation such as the absence of eyes, partial fusion ot 

 two bodies, fusion of the eyes on the median line. These changes were 

 coincident with the stage of gastrulation.|| 



In lecturing on the denizens of the aqueous kingdom, on Friday last, 

 at the Royal Aquarium, Mr. A. Carter referred to deformities that exist 

 among fish. In 1885 and 1886 he had examined thousands of salmon and 

 trout fry at South Kensington, on their emerging from the ova, and found 

 one case of deformity in every thousand, and one case of monstrosity such 

 as twin and dual-headed fish in every four thousand."^ 



Though as said above these forms are usually inexplicable, yet their 

 dependence on the chances of outside conditions in some instances at least 

 is, indicated in the following passage taken from Darwin's Animal and 

 Plants under Domestication (p. 279). 



*Proe. of Bost. Nat. Hist. Soc, Vol. ix, p. 1.S3. 



t American Naturalist, Vol. xii, pp. 594, 751. 



X Zo61og>' of Ohio, p. G90. 



? Paclcard's Guide to the Study of Insects, p. 84. 



1! See American Naturalist, for 188G. 



^ Nature, Jan. 6th, 1887, page 231. 



PROC. AMER. PHILOS. SOC. XXIT. 125. P. PRINTED MAY 20, 1887. 



