408 SUMMARY OF CURRENT RESEARCHES RELATING TO 



in Bufo vulgaris Laur., one of those dry statistical studies with curves 

 and formulas which will probably form part of the foundation of a 

 securer Aetiology. 



Variation in Catfish.* — C. H. Eigenmann and U. 0. Cox record 

 various examples of saltatory variation, and among them some intei'esting 

 abnormalities in Ameiurus melas. In nine specimens taken at random 

 from a brook in a cave, variation in regard to the barbels was found in 

 the majority of cases, supplementary barbels being usually present. 

 The specimens form a series, showing apparently that the left side is 

 leading the way in the variation, but that there is a tendency towards 

 the acquisition of bilateral symmetry. The authors believe that the 

 specimens must have been derived from a common ancestor, and that 

 the variation is progressive. 



Otoliths of the Frog.f — M. Marage finds that the ear of the frog 

 contains a liquid of undetermined nature containing in solution bicar- 

 bonate of calcium and traces of bicarbonate of magnesium, with crystals of 

 insoluble carbonates. The mixture has a high density, and is well suited 

 to conduct sound. One of the functions of the otoliths is to maintain as 

 constant as possible the acoustic conductibility of the medium. 



Do Fishes distinguish Colours ? J — K Zolotnitsky has made a 

 number of experiments with tench, carp, and other fishes, which have 

 convinced him that they have a marked preference for red objects, e.g. 

 little pieces of woollen thread the size of Cluronomus larvae This was 

 especially well seen in forms accustomed to feed on these larva? and in 

 those that were hungry. Green and white threads were ignored ; yellow 

 threads were sniffed at. He maintains that the question cannot be dis- 

 missed with a hurried negative answer. 



Hygienic Habits of Animals.§— Dr. E. Trouessart discusses (1) the 

 disposal of refuse and excrement at a distance, including the eating of 

 the placenta and the hygienic devices of the bee-hive ; (2) the removal 

 or burial of corpses ; (3) the ventilation of dwellings ; and (4) the pre- 

 servation of food-supplies. Most of the facts are familiar, but it is 

 useful to have them collected, and their presentation is picturesque. 

 Dr. Trouessart also discussed in a subsequent lecture || the relations 

 between zoology and medicine, illustrated especially by reference to 

 Pasteur's work on pebrine, Laveran's researches on Haeinatozoa, and 

 Metchnikoff's studies on phagocytosis. 



Maternal Devices.*!— Xavier Easpail discusses some of the "ruses 

 mater nelhs " exhibited by female animals in securing their young from 

 enemies against which the maternal strength and care cannot directly 

 cope. 



Marks on Dolphins made by Cuttlefish. ** — Prof. D'Arcy W. 

 Thompson refers to the figure of Delpliinus novsezelandise in the ' Voyage 



* Amer. Nat., xxxv. (1901) pp. 33-8 (2 figs.). 



t ( 'omptes Rendus. cxxxii. ( 1001) pp. 1072-4 (2 figs.). 



1 Arch. Zool. Exper., ix. (1001) Notes et Revue, pp. i.-v. 



§ Bull. Soc. Zool. France, xxvi. (1001) pp. 10-20. II Tom. cit., pp. 32-45. 



f Tom. cit., pp. 53-61. ^ 



** Ann. and Mag. Nat. Hist., vii. (1901) pp. 503-5 (1 fig.). 



