THE NAITILUS. 33 



to be a deformed or abnormal Ainalla. Tliis view was adopted by 

 Tryon and others; Morch, Binney and Fischer having doubted the 

 very existence of such a slug. 



In examining the slugs of the Vienna Museum lately, Dr. Babor 

 found Fitzinger's specimens, and he also obtained fresh individuals 

 collected by Dr. Sturany in northern Steiermark, and by Dr. Wer- 

 ner in Montenegro. These specimens prove that Aspidoporns Umax 

 is not only a valid species, correctly observed by Fitzinger, but it 

 belongs to a special group of at least subgeneric value. 



The mantle is formed as in Amalia, having the impressed " horse- 

 shoe," but there is a small orifice which in some specimens penetrates 

 to the shell-sack, while in others it is merely a short, sharp impres- 

 sion, not penetrating through the mantle. The shell-plate is small 

 and moderately thick. Pallial organs and nervous system as in 

 Ama/ia, and the jaw and teeth are also not peculiar, except that the 

 former is a little notched in the middle, below. The intestine is 

 somewhat peculiar. There are six longitudinal folds, G 5 and the 

 lower part of G B (forming the last posterior loop), being independent 

 of the spiral torsion of the normal A mafia folds, lying to one side. 

 There is no coecum. 



In the genital system the accessory gland (characteristic of 

 A matin), i completely wanting. 



Dr. Babor, in discussing the systematic position of Aspidopoms 

 and Am alia, gives evidence for regarding them as independent of the 

 Limacidce, and as a branch from the family HdicidcE (in the narrow 

 sense). The main argument for this view is that the embryologic 

 origin of the spermatheca is diverse in the two groups, Amnlia being 

 of the Helicid triaule type, while Limax is of the diaule type. An 

 adequate discussion of this question would require more space than is 

 available in this place ; but it should be said that the well-developed 

 pedal grooves show Ama/ia to be a typical Aulacopodous snail, and, 

 therefore, far removed from the Helicidi?; while the particular modi- 

 fication of the retractor muscle system distinctly points to the Lima- 

 cida. This is not likely to be a wholly independent parallel evolu- 

 tion. Moreover, I fail to s^e any such resemblance between the 

 intestinal arrangements of Aspidopyrtts and the Helices as Dr. Babor 

 alludes to, though the gut is wholly unlike that of Limax. 



It is very gratifying to have the real existence of Aspidoporus 

 proven, especially as the genus is undoubtedly more primitive than 



