ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 185 



uuknowii, is transmitted by the bite of a mosquito, Stegomyia fasciata, 

 which bites at night when adult, and is only dangerous twelve days 

 after it has bitten an infected patient. Phlebotomous fever, or " three- 

 days' fever," or " summer influenza," is transmitted by certain kinds of 

 sandflies. Sleeping sickness, due to Trypanosoma gamhiense and T. 

 rhodesieiise is transmitted by Glossina palpalis and G. morsitans respec- 

 tively. The reservoir is in native game. European relapsing fever, 

 due to Spirocliaeta recurrentis, is transmitted probably by lice. African 

 relapsing fever, due to S. duttoni, is transmitted by ticks {Ornithodoros 

 moitbata). Bubonic plague is transmitted from rat to man by Pnlex 

 c.heopis, the rat-flea. Elephantiasis, due to a Nematode {Filar la) is trans- 

 mitted by mosquitoes. A number of other diseases are discussed. 



Identity of Heliotropism in Animals and Plants.* — Jacques 

 Loeb and Hardolph Wasteneys have been led by experiment to this 

 conclusion. They regard the heliotropic reactions of certain plants and 

 animals as due to a chemical action of light. There seem to exist two 

 types of heliotropic substances, one with a maximum of sensitiveness 

 (or absorption) in the yellowish-green (near A = 534 /x/a), and the second 

 with a maximum of sensitiveness in the blue (near A = 477 /a/x). Visual 

 purple is a representative of the former type, and occurs in the Proto- 

 zoon (Jhlamydomonas (often claimed as a plant), in Daplmia, and many 

 other organisms. The photo-sensitive substance, with the maximal 

 sensitiveness in the blue, is found in Euglena, in many plants, and in 

 certain animals, such as Eadendrium. The two types of photo-sensitive 

 substances are distributed independently of the systematic boundaries 

 between plants and animals. 



Abnormality in Mandible of Chimsera.f — W. E. Colhnge describes 

 a small plate-like bone, immediately behind the lower posterior border 

 of the mandibular symphysis, in Ghimaera monstrosa. In another speci- 

 men it had a median wedge-like portion, flanked on each side by a 

 similar tapering piece. It is suggested that it may be a reversionary 

 vestige of a presymphysial mandibular tooth which has got turned back. 

 The minute structure of the abnormal bone is quite distinct from that 

 of the ordinary bones of fishes. The nearest condition is the state of 

 certain bones in post-larval Pleuronectids. There is a series of closely 

 massed strands, forming a meshwork of spongy material. 



Organ of Jacobson in Insectivora.| — R. Broom describes the struc- 

 ture of the organ of Jacobson in Talpa, Centetes, and Ghrysochloris, and 

 his results, taken along with those reached in a previous study, go to 

 show that the " Insectivora " do not form a natural order. In Erina- 

 ceus, Gyrnnura, Talpa, Sorex, and Centetes, the organ of Jacobson ends 

 in a long duct opening into the naso-palatine canal near its anterior part. 

 Jacobson's cartilage in each passes forwards with the duct, and the naso- 

 palatine canal is supported by an anterior process of the posterior nasal- 

 floor cartilage. Whatever subdivision may on other grounds be made of 



* Science, xli. (1915) pp. 328-30. 



t Ann. Nat. Hist., xxi. (1915) pp. 110-3 (4 figs.). 



X Proc. Zool. Soc, 1915, pp. 347-54 (2 pis.). 



