40 KKIDIHjOF OKI. AM). M.-N. KI. 



fields and tlic id^c of foliiferou.s trees, especially tho.se sensitivf- to cold 

 („kuldskjærc lovtrær"), such as Coryliis Avcllana, (Juercits, iilid [xirvifului 

 and Uhnns niontana. In these places it may be collected in hundreds under 

 dead leaves, pieces of bark and so on. Not rarely it is found buried several 

 centimetres in the earth, and olten appears to hibernate in this position, 

 being found inert, enclosed in earth as soon in spring as the fro.st in the 

 ground has disappeared; several times I have seen these specimens in an 

 almost vertical position in the earth. 



This species, also, has a considerable facility for "spinning" mucus 

 threads from the tail groove, and the young especially may be seen lowering 

 themselves several centimetres in this fashion. 



Their food chiefly consists of vegetables, and they may occasionally 

 be found on fungi. But animal food is also accepted, and KC.nkel reports 

 them as devouring dead snails and slugs. 



The congress has very seldom been observed ; Taylor mentions it 

 to have been seen by E. J. Lowe, according to whom it lasts only for 

 about ^/4 minute. The spermatophore was unknown until I found it in five 

 specimens collected on the 30th of June at Vestre Aker near Kristiania 

 (for description, see reproductive organs). 



The laying has been examined by Kunkel; it goes on for two months, 

 and during that time 3 — 5 hatches are deposited, each of 10 — 39 eggs, 

 the total number of eggs varying from 104 to 123. They are whitish, 

 always oval shaped, 2,8 — 3,5 mill, long and 2 — 3 mill, broad. 



As regards development, the investigations of the same author may 

 be briefly quoted. The young are hatched after a period of three weeks 

 or more, according to the temperature, and then appear bluish white, 

 with two dark longitudinal bands on the shield and the back, and with a 

 white stripe along the middle of the back. As the animals mature, the 

 yellow pigmentation appears in var. circnviscripta, the smallest young of 

 which, however, are difficult to distinguish from var. nigra. 



They reach maturity in 8 — 9 months, and live to 12 — 13 months of age. 



According to measurements I have taken of about 800 specimens it 

 is obvious that all sizes are to be found at the same time, irrespective of 

 which period between April and October the collections are made. 



Arion hortensis Férussac. 



1819 Arion hortensis Férussac, Hist. Moll., p. 65, pi. II, fig. 4 — 5. 



nee. Arion hortensis Férussag a p u d Westerlund, Exposé critique, Nova Acta Soc. 



Upsal., p. 35 (1871). 



— — „ — — — Jensen, Indberetning (1872). 



— — „ — — — EsMARK, Journ. of Conch., vol. 5, p. 103 (1886). 

 Diagnosis. External characters : body slender, about 4 cms. long. Colour bluish dark 



in the young, dark brown in fully developed individuals ; foot-sole orange. Lateral bands 

 black, on the shield the^' run close to the edge, at the highest with a narrow pale line outside. 



