90 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. lv. 



remain in a central protoplasmic bag. The cells of the egg- 

 apparatus, as well as the antipodal cells, are at first spherical 

 on their surface next the cavity of the embryo-sac, but later 

 the antipodal cells become concave. The two nuclei in the 

 protoplasmic bag conjugate thus : — The nucleus from the 

 antipodal end travels towards the sister-nucleus of the ovum ; 

 each of the nuclei shows a large nucleolus with two small 

 bodies with a dark central granule, reminding one of two polar ■ 

 bodies ; the two nuclei come in contact, aud become flattened 

 against one another, thus showing their indifference ; then 

 the nucleolus from the antipodal nucleus conjugates with 

 the nucleolus of the sister-nucleus of the ovum, the former 

 divesting itself of a nucleolar bag. After conjugation a 

 remarkable series of changes takes place in the newly-formed 

 nucleolus of the endosperm-nucleus, but my researches are 

 not quite finished in this direction. 



Ax Account of Presslek's Growtii-Boreij. By Prof. 

 William Somerville, D.Oi^c, B.Sc, F.R.S.E. 



(With Woodcut 6.) 



This useful little instrument is the invention of the late 

 Dr Max Pressler, Professor of Applied Matliematics in the 

 Saxon School of Forestry at Tharand. Although still 

 retaining its essential characters, it has been improved as 

 regards a few minor details by Dr Neumeister, Pressler's 

 successor in Tharand. The agents for its sale are the 

 publishing firm of IMoritz Perles, 4 Seller Gasse, Vienna, and 

 TL Thomas, 3 Thai Strasse, Leipzig. It was formerly made 

 in three sizes, but now only in two — viz., size A, the 

 shallow Ijorer for use upon both hard and soft-wooded trees, 

 and size B, the deep borer, for use in the case of soft-wooded 

 trees only. The former costs 13s. 6d., and can sample the 

 wood to a depth of about 2^ inches, while the latter costs 

 l7s., and can pierce soft wood to a depth of about 6 inches. 

 For ordinary purposes I much prefer the shallow borer. 

 It is shorter, and is therefore more convenient both to carry 

 and to use, and it is less liable to break. It certainly does 

 not sample soft wood to so great a depth as the other, but 

 in the majority of cases one does not require to investigate 



