INTRODUCTION. 



L nlike many other countries, Norway possesses no real introduction 

 to the study of its pulmonates. the need for such a work, however, being 

 evident from several erroneous statements concerning the Norwegian snails 

 and slugs. Therefore, as regards the Ariojiidae, I have tried to rectif\' this 

 disadvantage, and the present paper is the result of my investigations. 

 Whilst setting forth several new results, (vide Summary) I have tried to 

 give a general survey of the five Norwegian members of the family. 



The material for the investigations was chiefly derived from my own 

 collections made in Southern Norway (/. c. that part south of the Trond- 

 hjem Fjord) in the years 19 13 — 20. For the funds I am under a deep 

 obligation to '^Professor R. Colletts Icgat til iindersokelse og bearbcidelse av 

 Norges fait)ia\ In addition the collections of the Museums at Kristiania, 

 Bergen, Trondhjem and Tromso have been kindly placed at my disposal, and 

 this has been of special value when checking the Arions published by 

 BiRGiTHE EsMARK and O. S. Jensen, as at that time erroneous determinations 

 of several species of this family were not so very rare. F'inally I would 

 gratefuUv remember my many friends who have been so kind as to collect 

 slugs in various parts of the country. 



The investigations were carried out at the Zoological Laboratory of 

 the Kristiania University, where Professor Kristine Bonnevie, Ph. D., the 

 curator of the Zoological Institute, gave valuable aid as the work was pro- 

 ceeding. I beg to express to her my deep gratitude for her advice. 



Methods. The technical appliances and methods necessary for the 

 anatomical study are ver}' simple. The slugs are cut open with a pair of 

 scissors along a line on the left side of the body, in order to keep the shield 

 and the underlying parts intact. From the extreme points of the line of 

 dissection a cut is made to the right, and the body wall may be lifted 

 up to the right side. The animal is then fixed to the bottom of a cup 

 covered with wax, which should be of a dark colour; the pins decline out- 

 wards. The various organs may then be separated from each other with 

 comparative ease I fig. 2). As a rule only the reproductive organs are 

 examined. 



The dark, horseshoe shaped jaw is cut free by means of a slender 

 scalpel, is placed under water so as to be picked free from the adherent 



Vid.-Selsk. Skr. I. M.-N. Kl. 1922. No. 5. 1 



