Mr. T. D. A. Cockerell's Notes on Slugs. 107 



Described from a specimen, " purchased at Stevens," in the 

 British Museum without locality. 



Ibycus fssidens, Heyn., 1862, was very insufficiently 

 described ; but as it agrees with sikkimensis in all known 

 points and was from the same neighbourhood, though at a 

 higher altitude, there seems no reason for regarding it as 

 distinct. Heynemann's name has priority. Ibycus, as a 

 generic title, may perhaps be used for a large series of forms 

 allied to jissidens, including I. pupillaris (Humb.) from Java. 



Limax problematicus, Fer., pi. viii. F. figs. 13-17, belongs 

 to Ibycus, and seems allied to sikkimensis. 



Ibycus siamensis, sp. n. 



Length about 30 millim., mantle 17^ millim. long. Mantle 

 prolonged anteriorly, as usual in Ibycus. Shell that of 

 Oirasia, but exposed like Austenia, apparently not whorled, 

 thin, convex. There is a black band on each side of the 

 keel, as in Africarion ater, vars. aterrimus and cinereus, 

 though higher up, i. e. next to keel, not a little way from it. 

 Colour dark grey above, more or less mottled with darker, 

 sides below mantle pale. Foot-fringe alternating whitish and 

 grey. Sole pale ochry, unicolorous. 



Described from two alcoholic specimens from Siam in the 

 British Museum. It is a rather puzzling form, in some ways 

 resembling both Africarion ater and Ibycus pupillaris in some 

 of their varieties. Perhaps it will prove to be a subspecies or 

 race of Africarion ater. 



LACONIA, Gray. 



Laconia Ferussaci, Gray, is founded on Ferussac's figure of 

 " Vitrina, sp.," on pi. viii. P. figs. 10, 11, 12. Gray gives 

 the shell as covered by the mantle, but the figure looks as if 

 a Helicarion-Yike shell had been removed. There is a well- 

 formed mucus-pore. A little slug in the British Museum 

 from Ceylon is evidently similar ; the shell is gone. There 

 is an anterior extension of the mantle. 



Laconia is probably identical with Austenia j but as some 

 uncertainty remains, I do not adopt the earlier name of Gray 

 for that genus. 



[To be continued.] 



3 Fairfax Road, Bedford Park, Chiswick, W., 

 November 3, 1890. 



