56 



THE NAUTILUS. 



anterior end ; color dark coffee brown, including sole ; mantle 

 a shade darker than body ; no markings ; lateral pedal furrow 

 below middle of sides of sole; median area of sole about as 

 wide as either lateral area. Penis-sac curled like a letter s. 

 Shell 2y 2 mm. long, a fraction over 1 mm. broad, formed as 

 in the Antigua specimen. Marginal teeth mostly simple, but 

 the inner ones with small side cusps. The stomach contained 

 vegetable remains, including numbers of two-armed hairs, 

 which Dr. Eamaley identifies as being almost certainly those 

 of a leguminous plant. 



The character of the penis sac, wholly without any apical 

 branched gland, places both these species in the group of 

 A. l&vis, and separates them from A. agrestis. The jaw also 

 is entirely of the l&vis type. It is a most extraordinary thing 

 that slugs from the moist tropical coast region of Guatemala, 

 and others from the highlands of that country, apparently 

 native species, should so closely resemble the slug found at 

 high altitudes in the mountains of Colorado, and that common 

 in northern Europe. The fact of the wide distribution of the 

 l&vis type has long been known, but one remains amazed at 

 such migrations combined with such conservatism ! 



The same type of slug occurs at high altitudes in Asia. The 

 character of the marginal teeth in the Quirigua slug agrees 

 quite closely with that of A. tibetanus God win- Austen (Rec- 

 ords Indian Museum, II, 1908, p. 414), from an altitude of 

 14,500 feet. The inner angle of the first laterals (admedians 

 of God win- Austen) is less prominent in the Tibet slug, but 

 the drawing is not very detailed. In attempting to distin- 

 guish the Guatemalan slugs from veritable A. Iccvis, we are 

 almost at a loss. The total absence of any angle or tooth on 

 the marginals in the Antigua slug appears distinctive, but the 

 far northern A. lavis hyperboreus is figured as having just 

 such marginals. The shell in our specimens, except for the 

 narrow form, shows nothing characteristic; it has not the 

 obtusely keeled form of that of A. berendti and A. hemphilli 

 pictus. The slight differences shown in the figures of the 

 middle and first lateral teeth of the Antigua and Quirigua 

 specimens are apparently of no particular significance, as the 



