174 SUMMARY OF CURRENT RESEARCHES RELATING TO 



deep black colour. After eight days of captivity, it gave birth to 

 fifteen black offspring. The normal number is three to five, and twelve 

 has been recorded by Fatio as altogether exceptional. 



Habits of the Arboreal Urodele Autodax lugubris.*— W. E. Ritter 

 finds that the usual breeding place of this " unsalamander-like sala- 

 mander," whose close kinship to the other Plethodons cannot be 

 doubted, is in holes in trees (Quercus agri folia). Some were taken from 

 holes at a height of thirty feet at least : in some of the largest cavities 

 as many as twelve individuals were found ; more commonly a hole con- 

 tained two, or occasionally but a single Autodax. Several facts indicate 

 pretty clearly that in some cases all the inhabitants of a single chamber 

 were close of kin, constituting in fact a family. Most of the cavities 

 occupied had very narrow orifices. 



The egg clusters, each containing from twelve to eighteen eggs, each 

 egg with its own pedicle about two centimetres in length, were usually 

 suspended from an overhanging surface, where the parent was able to 

 bring its body into contact with them. Both parents, w r hich are not 

 distinguished by secondary sexual characters, may participate in the 

 office. The animals seem to exercise more or less of an active defence 

 either of themselves, or of the eggs, or of both. The unusually large 

 teeth are used viciously in " showing fight." Experimental study on 

 the behaviour of this unique Urodele should yield very interesting 

 results. 



Respiration in Torpedo.f — E. Couvreur finds that in Torpedo mar- 

 morata the water may enter by the gill-clefts, the spiracles, and the 

 mouth, but always passes out by the clefts. There is a synchronism 

 between the movements of the heart and the respiratory movements, as 

 Jorgen Thesen observed in Tcleosts, and as the author previously noticed 

 in the lamprey. 



Labyrinth of Fishes. f — Tycho Tullberg has made experiments on 

 various fishes which lead him to conclude that the labyrinth of the ear 

 is not an equilibrating organ, nor an organ " of static sense " (Breuer), 

 nor a " tonus-labyrinth," nor the seat of "a spatial sense" (v. Cyon). 

 Tt is perhaps in some degree an auditory organ, but it is primarily and 



rincipally sensitive to the movements — both currents and undulations 

 —of the surrounding water, with its nervous centre probably in -the 



erebellum. 



Wild Horses. § — J. Cossar Ewart gave an interesting lecture on 

 Przewalsky's horse, which he regards as a true and valid species. He 

 compares it with the Kiang and with various hybrids which he has 

 reared. " If Przewalsky's horse is neither a Kiang-pony mule nor a 

 feral Mongolian pony, and if, moreover, it is fertile (and its fertility 

 can hardly be questioned), I fail to see how we can escape from the 

 conclusion that it is as deserving as, say, the Kiang, to be regarded as 

 a distinct species. Granting Przewalsky's horse is a true wild horse, 

 the question arises : In what way, if any, is it related to our domestic 



* Amer. Nat., xxxvii. (1903) pp. 883-G. 



t Ann. Soc. Linn. Lyon, lxxxix. (1903) pp. 78-9. 



% Bihang. k. Svensk. Vet.-Akad. Handl., xxviii. Afd. 4 (1903) No. 15, p. 25. 



§ Nature, lxviii. (1903) pp. 271-3 (3 figs). 



