ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 4J 



(anterior) surfaces of the mandibles, and are similar on the two sides. 

 In Selenogyra the apparatus consists of a number of rows of bacilla-. 

 arranged in a somewhat crescentic manner, the bacillse of the outer 

 rows being the largest. In Euphrictus spinosus g. etsp.n, (which the 

 author describes) the organ is practically reduced to an oblique row of 

 live strong spines. 



Activities of Araneads. ; - -T. H. Montgomery has made a study 

 of the age-differences in the snares of two Argiopids, with regard to 

 the problem as to whether the snare becomes more complex as the 

 spider grows older. The forms studied were Epeira sclopetaria and 

 E. marmorea, both of which construct large, vertical, orbicular webs, 

 which are easily measured. Webs made by immature and by adult 

 spiders were compared in regard to (1) number of radii, (2) number of 

 spiral loops, and (3) greatest diameter of the viscid spiral (orb proper). 

 The age-changes in both species are greatest with regard to the 

 diameter of the viscid spiral, less with regard to the number of its 

 loops, and least with regard to the number of radii. The first snare of 

 the spiderling has all the parts of that of the adult ; but with increasing 

 age the thread becomes thicker, the web larger, and there are a few more 

 radii and loops. The differences are due to the increased weight of the 

 spider and the increased size of the spinning-organs, and the consequent 

 greater amount of silk. There is nothing either in the making of the 

 snare or of the cocoon to indicate that the spider learns by experience. 



Notes on the senses of touch and sight in snare-making spiders, and 

 on the cocooning of Loxosceles ri/fescens, are appended. 



Development of Spiders.| — P. Wallstabe describes the development 

 of the form of the body in AgeUna labyrinthka, paying particular 

 attention to the appendages, the segmentation of the ccelom, the cavity 

 of the head, and the like. 



Hydrachnids from Tiree.}— Wm. Williamson reports Thyas longi- 

 rostris Piersig and Tiphys Uliaceus Midler, which have not, been recorded 

 before for Scotland. He also got Hydryphantes ruber De Gecr, which 

 has been already recorded. 



Malleoli of Solpugidse.§— IT. Riihlemann gives an account of the 

 minute structure of the so-called malleoli or " coxal raquettes " on the 

 fourth appendage of Solpugidae. He describes the innervation, blood 

 supply, tracheae, and so on, and then goes into the details of the sens 

 cells and nerve fibres. The. function of the organs— probably smell 

 taste— remains undetermined. Their resemblance to the pectines of 

 scorpions is emphasized. 



Podosomata of Temperate Atlantic and Arctic Oceans. j |— A. M. 

 Norman revives Leach's title Podosomata for the Pycnogonids or 



* Amer. Nat., xlii. (1908) pp. 697-709. 



t Zool. Jahrb., xxvi. (1908) pp. 683-712 (2 pis. and G figs.). 



% Ann. Scot. Nat. Hist. (1908) pp. 161-2. 



8 Zeitschr. wiss. Zool., xci. (1908) pp. 599-639 (2 pis. and 



]| Journ. Linn. Soc. (Zool.) xxx. (1908) pp. 198-238 (2 pis I. 



