Qua I ierly Journal of Conchology. 411 



seen Arion horteiisis hang itself by a thread from a twig, and I 

 feel satisfied that it is a habit common to all the Slugs. 



The observations of Mr. Binney,* the eminent x\merican 

 Conchologist, upon the Slugs of his native country, are of such 

 interest that I cannot refrain from quoting considerably from 

 them. He says "All the species which have yet come under our 

 notice possess the power of suspending themselves in the air by a 

 gelatinous thread During the whole operation the loco- 

 motive disc is in active uiidulatory motion, in the same manner 

 as when in ordinary progression. It appears in thi, way to guide 

 and force toward the extremity the mucus which is secreted on 

 its surface, and which, collected at its extreme point forms the 

 thread. The Slug often pauses in its descent, and extends its 

 tentacles and its whole body in various directions, as if seeking 

 some object on which to make a lodgment. . . . It is mostly 

 however when they are young, or at least not grown to their full 

 size, that they enjoy this powerf . . . They often remain 

 suspended in mid-air for a time, and it is not unlikely that there 

 is some pleasurable sensation in the act, which induces them 

 thus to prolong it. We have seen the descent practised by 

 every one of our /.tlantic species," The two American species 

 of the peculiar genus Tehennephonis, Binney, are included in his 

 list. 



Megalomastoina sus^ensiim, mentioned by Guildingj (now 

 called M. Guildiugianum, Pfr.), derived its first name from its 

 habit of suspending itself from the branches of trees by a thread. 



My excellent correspondent Mr. J, S. Gibbons, ]\I.B., to whom 

 I am indebted for much information and many specimens of the 



* L. and F.-\V. shells of N, A., part i, pp. 8-9, Washington Smith- 

 sonian Inst., 1869. 



I This is the case with all Mollusks, so far as I have observed. 



+ Giulding, quoted by Woodward, "Manual of the Mollusca," p. 209. 



