| OCR Text |
Show 850 MR. W. BATESON ON THE [Dec. 3, view of their physiological identity, though perhaps morphological non-correspondence. On the other hand, the last mentioned suggestion is not certain, especially in view of a statement of Mayer upon the lung-muscle of Pipa, which I have quoted in m y paper upon that Amphibian. Mayer refers to the origin in Pipa of a lung-muscle from the ilium which I have not found myself, but which corresponds with what I have found in Xenopus. Apart, however, from the lungs, there is so great a resemblance between the entire musculature which goes to form what I have ventured to term the diaphragm, that I cannot look upon it as a case of convergence due to similar physiological needs. The only possible test for discriminating between morphological resemblance and a likeness due to similar needs would appear to be the complexity of the structures in question. Judged by this test, I am inclined to regard the new facts put forward in this paper as evidence of relationship between Xenopus and Pipa. 3. On the Colour-variations of a Beetle of the Family Chrysomelidee, statistically examined. By W . B A T E S O N, M.A., F.R.S., Fellow of St. John's College, Cambridge. [Eeceived December 3, 1895.] (Plate XLVII.) At a meeting of the Society on M a y 1, 1894, I exhibited living specimens of Goniodena variabilis in illustration of the remarkable range of colour-variation in the species. Since then I have had opportunities for a fuller investigation of the matter, and tbe following paper is an account of the results obtained. G. variabilis1 is a small beetle, about \ in. long, belonging to the family Chrysomelidse. It lives on Spartium retama, a plant allied to the C o m m o n Broom, very generally distributed in hilly places in the south of Spain, though absent, I believe, from the limestone districts. This plant grows as a bush varying in height from one to about seven feet according to the situation, humidity, and exposure. The stunted form is dense and compact, having stout branches spreading out more or less horizontally, giving off erect leaf-bearing stems set closely together. The tall form is slender and graceful, and its leaf-bearing stems are generally pendulous and wavy. In their extreme forms these two conditions of the plant differ considerably from each other, but all intermediate conditions are found. In colour the stems of this Spartium are of a dull greenish grey. The surface is marked with irregular longitudinal ribbings, which give it an appearance of faint striping. It is upon the stems of this plant that the beetles live, infesting both forms indifferently. W h e n at rest they are commonly seen sitting with their heads in the. axils of the twigs, their bodies being closely pressed against 1 The genus Gonioctena is Phytodecta of the Munich Catalogue. The species G. variabilis is the Phytodecta agrota of Fabr. and Suffr. |
