Miscellaneous. 77 



to explain how such powerful mineral acids can be secreted in a 

 free state in the perfectly healthy organism of a living animal. 



Tlie first of these questions is to a certain extent answered by 

 Troschel. He has seen the stream of liquid projected by the animal 

 issue from the mouth and attain a length of several feet. This is an 

 indication which the physiologist must not allow to pass unappreciated. 

 It appears rational to conclude therefrom, that at least a great part 

 of the salivary liquid is not employed in digestion. On the other 

 hand, it is very probable that the Doiiinn makes use of it as a defensive 

 weapon. The shell of Doliinn has a very wide opening, and is destitute 

 of a protective operculum, so that the animal is exposed to every kind 

 of attack. It is probable that it defends itself against its enemies by 

 means of the sulphuric and nmriatic acids of its saliva. We must 

 not forget, however, that as the animal lives in water, its saliva cannot 

 act at any great distance. We might suppose that the saliva is 

 employed for two different purposes, on the one hand for defence, 

 and on the other for digestion. This latter function, however, 

 appears to be contradicted by an observation of Troschel's. In the 

 stomach of many specimens of Doliitm he found the debris of Fuci 

 bearing small animals with calcareous shells, such as Polypes, Ser- 

 pulce, &e. When exposed to the action of the saliva, these fragments 

 of calcareous shells were dissolved, with a strong effervescence, in less 

 than a minute. We may therefore conclude that the Fiici had not 

 been in contact with the saliva either before, or during, deglutition. 

 The saliva, consequently, has probably no relation to digestion. 



It is curious that the membranes of the animal itself which are in 

 contact with the acid are not attacked thereby. This liquid also has 

 no effect upon the shell of the Dolium, especially upon its inner 

 surface, which is covered by a delicate polished varnish, unalterable 

 by acids. 



The Dolia are not endowed with the faculty of perforating stones ; 

 but the mere fact of the secretion of a free acid in these Mollusca, 

 shows that it is not impossible that perforating animals may secrete 

 a substance capable of chemically acting upon calcareous rocks. It 

 is true that the perforating Lamellibranchiate moUusks are destitute 

 of salivary glands, but it is not impossible that some other part of 

 the body may assume the secretion of an acid liquid. — Mo7iatsber. 

 der Akad. der Wiss. zu Berlin, August 1854, p. 486. — From the 

 abstract by E. Claparede in Bibl. Univ. de Geneve, February 1857, 

 p. IGl. 



Note on the occurrence of the Harvest Mouse in Cornwall. 

 By Charles William Peach. 



In the ' Zoologist ' for the present month, at page 5592, I observe a 

 communication from Mr. E. H. Rodd, mentioning the occurrence of 

 the Mus 7nessoriys at Penzance, and of its not having been noticed in 

 Cornwall before. I find in Couch's Cornish Fauna, part l,page 7, 

 that it is common, and so it occurred to me, for during my residence at 

 Goran Haven, this beautiful little creature was well known to me, 

 from having seen it and its nest on the stems of corn in the fields, and 



