742 SUMMARY OF CURRENT RESEARCHES RELATING TO 



mimicking them obtains no protection in the vicinity of these birds 

 There is qo bird in Ceylon known to eat butterflies that distinctly dis- 

 criminates as an adult between one species of butterfly and another. 



1 1 has been shown that there is a gnat, destruction of butterfly life 

 in the dry zone, and that here, if anywhere, Mullerian or Batesian 

 mimicry might be induced, but the destroyers are largely migratory, and 

 their attacks are not selective. 



The number of broods of butterflies which occur between the ter- 

 mination of tasting experiments in one year and the commencement of 

 them in the next, is so great that any influence which could be wrought 

 by such is almost inappreciable. 



The little evidence available shows that young Ceylon birds imitate 

 their parents in their choice of food ; but as regards butterflies, the fact 

 that there is no discrimination shown by adults leads one to conclude 

 either that few or no tasting experiments are undertaken in youth, or, 

 what is more probable, that their taste with regard to them is indifferent. 



So far as an accurate knowledge of one species goes it is definitely 

 shown, that that form of mimicry represented by wet and dry season 

 forms (cryptic defence) is not produced for the protection of the species, 

 inasmuch as many (four) succeeding broods of the wet weather form 

 maybe found under dry season conditions without detriment to the species. 



Different kinds of Hair.* — K. Toldt has given a useful account of 

 the different kinds of hairs, distinguishing three main types, bristles 

 (Grannenhaare), wool, and " Leithaare." The " Leithaare " are longer 

 and stronger than the bristles ; they are stiff, sparse, and isolated. 

 According to the author, the most primitive kind of hair is the " Leit- 

 haar," then the bristle, then wool-type. Special forms of hair, such as 

 those in some bats, in the tail of some porcupines, etc., are described. 

 The disposition of the hairs on the body of representative mammals is 

 also discussed. 



Composition of the Lower Jaw.f — E. Gaupp finds that the "gonial," 

 a membrane bone of the primordial lower jaw, is the so-called " angular " 

 of amphibians, the processus anterior mallei of mammals, and has a varied 

 history in reptiles. 



In amphibians, the primordial lower jaw may show a posterior and 

 anterior ossification (articular and mento-mandibular), and the following 

 membrane bones : dentary, opercular ( = splenial), gonial, and excep- 

 tionally an element called " angular." 



In Sauropsida the articulating end of the primordial lower jaw ossifies 

 as the articular, and there may be as many as six membrane bones — 

 dentary, opercular (= splenial), gonial, angular, supra-angular, and 

 complementary. 



In mammals there arise on the primordial lower jaw three membrane 

 bones— the definitive mandible (corresponding to the dentary), the 

 tympanic (probably = angular), and the processus anterior mallei 

 (== gonial). From the articulating end of the primordial lower jaw the 



* Ann. Natur. Mus. Wien, xxiv. (1910) pp. 195-268 (4 pis. and 1 fig.). See also 

 Zool. Zentralbl., xviii. (1911) p. 416. 



t Anat. Anzeig., xxxix. (1911) pp. 609-66 (6 figs.). 



