ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 419 



Structure of .Enigma aenigmatica Chemnitz.* — G. G. Bourne 

 recounts the distinctive peculiarities of this bivalve. His material was 

 collected from amongst the roots of the palm Nipa, at Sarawak. Some 

 of the more important facts recorded are here given. JEnigma re- 

 tains more of the typical features of a normal Lamellibranch than 

 Anomia. There is a specialised pallial muscle which acts as retractor of 

 the left gill. Adaptations for resisting desiccation during long exposure 

 to the sun and air are found in the thickening and corrugation of the 

 lower moieties of the mantle-lobes and in the existence of cgecal exten- 

 sions of the pallial cavity, which can be closed by the apposition of the 

 ciliated edges of ridges developed on the mantle and body-wall. The 

 animals are liable to be exposed for days together to the rays of a tropical 

 sun, yet they always remain moist and fresh. The kidneys and the 

 openings of the reno-pericardial ducts and gonaducts into the kidneys 

 are similar to those of Anomia ephippium. The gonopores have ciliated 

 funnels. An internal ciliated groove runs the whole length of the 

 caecum of the crystalline style. 



Arthropoda. 

 a. Insecta. 



Treatise on Insects.f — Antonio Berlese deals in fascicles 21 and 22 

 of his exhaustive and admirably illustrated treatise on insects with the 

 nervous system and the sense-organs. 



Factors influencing Insect Development. | — C. Hennings has ex- 

 perimented with a view to determining some of the factors influencing 

 the time of egg-laying and duration of the development period of insects. 

 His results show that in the case of the Chafer, Tomicm typographus L., 

 besides temperature, the amount of moisture is to be reckoned as a 

 regulating factor. With regard to egg-laying, increase of the moisture 

 in the atmosphere when temperature is high causes slight delay ; at low 

 temperatures the delay is considerable. Increase in the dampness of the 

 air may lengthen the whole period of development from 1-2 weeks, and 

 this hindering influence of increased moisture is more marked the lower 

 the temperature is. It effects at 21° a delay of 6 days, at 11° a delay 

 of 18 days. 



Assimilation of Carbon-dioxide by Chrysalids of Lepidoptera.§ — 

 Marie von Linden found that the chrysalids of PapiUo podalirias and 

 Hylophila prasinana, placed in a wet atmosphere charged with carbon 

 dioxide, absorbed the gas, and that instead of losing weight as normally 

 occurs at this stage, they became heavier. The nitrogen of the atmo- 

 sphere, as well as the elements of water, contributed with the carbon 

 dioxide to form an organic substance rich in carbon. 



■^a" 



Predaceous Insects and their Prey.]] — E. B. Poulton publishes 

 the flrst part of a memoir on this subject, which is the result of the 



* Quart. Journ. Micr. Sci., No. 202 (1907) pp. 253-95 (3 pis.). 



t Gli Insetti, Milano, 1907, pp. 585-648 (figs. 698-800). 



X Biol. Centralbl., sxvii. (1907) pp. 324-37. 



§ C.R. Soc. Biol. Paris, Ixii. (1907) pp. 360-2, 371-2. 



Il Trans. Entom. Soc. London, 1906, pp. 323-409. 



