450 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Mating" of Spiders.* — Lucien Berland has made minute observations 

 on the mating habits and sexual union in Scytodes velutina dehcatula, 

 Storena reticulata, Drassodes severus, D. lapidosus, Theridion denticu- 

 latum, Lycosa laciniosa, and Philseus chrysops, and his observations throw 

 an interesting light on the mental faculties and sensory acuteness of 

 these animals. We shall refer to three of his results. 1. The seminal 

 ejaculation is due to the blood-pressure, and the rhythmic movements of 

 the spines of the appendages (in Dysdera erythrina var. provincial is) 

 correspond to the beating of the dorsal vessel. 2. The structural com- 

 plexity of the copulatory organ is sometimes at least (as in Storena reti- 

 culata and Theridion denticulatuni) correlated with the mode of sexual 

 union. 3. Similar methods of sexual union occur in the same family, 

 but the same method may be observed in different families. Perhaps 

 there may be some phylogenetic suggestiveness in this. 



*• Crustacea. 



Muscular Reticulum of Mid-gut Gland of Crustaceans.! — W. 

 Pump has studied this in Gammarus, Asellus, Astacus, Cancer, and 

 other types, with special reference to the structure of the muscle. The 

 reticulum of the glandular diverticula consists of cross-striped annular 

 fibres and their longitudinal connexions. It appears to be embedded 

 on a structureless hyaline layer, the so-called tunica propria. The two 

 are in very close association. The annular fibres run more or less 

 parallel, usually at right angles to the longitudinal axis of the tubules. 

 In some cases (terrestrial Isopods) they lie obliquely. They are always 

 closer together near the apex of the tubule. 



Where the annular fibres fork, there are " fork-branches " given off 

 which form along with the annular fibres the transverse meshes. The 

 longitudinal connexions are lateral processes of the annular fibres, but 

 run parallel to the long axis of the tubules. They sometimes branch 

 and become connected with one another. Along with the annular fibres 

 the longitudinal fibres form the longitudinal meshes. Broad transverse 

 and narrow longitudinal meshes are to be seen on each tubule. 



Three kinds of longitudinal connexions are described — by connecting 

 filaments, connecting fibres, and " cleft fibres " (Spaltfasern). The 

 connecting filaments are extensions of the matrix-membranes (Grund- 

 membranen) beyond the breadth of the annular fibres. While the 

 membranes lie within the annular fibres, associated with their sheath, 

 the connecting threads extend over areas which are not filled with fibrillar 

 substance. 



The connecting fibres are cross-striped longitudinal connexions of 

 annular fibres, joined on to the latter by means of the matrix-membranes. 

 The " cleft-fibres " differ from the connecting fibres in the way in which 

 they are joined on to the annular fibres. The sheath of the annular 

 fibres is continuous with the sheaths of connective fibres and "cleft 

 fibres." 



The whole of the muscular network is a. syncytium. Its main fibres 



* Arch. Zool. Exper., liv. (1914) Notes et Revue, No. 5, pp. 109-19 (4 figs.), 

 t Arch. Mikr. Auat., Ixxxv. (1914) Ite Abt., pp. 167-219 (1 pi. and 2 figs.). 



