INVERTEBRATA, CRYPTOGAMIAj MICROSCOPY, ETC. 861 



rect it is clear that water cannot enter by them into the organ of 

 Bojauus.* 



Land Shells of Californian and Mexican Islands.f — Mr. W. G. 

 Binney gives an important contribution to the geographical distribu- 

 tion of land shells. 



The Mexican island of Guadelupe, 220 miles from San Diego, off 

 the west coast of Lower California, has been visited by Dr. E. Palmer, 

 and he found numerous fragments of snail-shells which had been 

 devoured by a species of mouse, the only land mammal on the island. 

 These appeared to belong to Arionta BowelU (Newcomb), found in 

 Lower California. A. facta occurred, a variety with open umbilicus, 

 like that found fossil on San Nicolas Island, California. Living 

 specimens of Binneya notahilis were brought from Guadelupe, found 

 also on the Californian island of Santa Barbara; it is very nearly 

 allied to if not synonymous with the Mexican genus Xanthonyx. 

 Thus it is supposed to have been first distributed from Mexico, then 

 to Guadelupe, thence to Santa Barbara. 



Pompeian Conchology. J — Dr. N. Tiberi gives a list of forty-four 

 species of shells found at Pompeii, and which had served for food or 

 been used by the Pompeians for ornament and other purposes, with 

 particulars of their relative abundance as well as of their distribution 

 and economy. 



Some were of eatable kinds as the oyster and mussel, Pecten 

 jacobcBUS, Venus ckione, Tapes decussatus, and several species of Helix. 

 Others adorned fountains, as Haliotis tuherculata, Murex truncidus, and 

 M. hrandaris, and were all of species still common in the Bay of 

 Naples. The Oriental pearl-shell (3Ieleagrina margaritifera) was 

 represented by only a single valve. The Pompeian ladies seem to 

 have attached considerable value to the Cijprcea or Cowry as amulets 

 against sterility, and among these shells were some of species from 

 the Ked Sea and Persian Gulf. A single specimen of the exotic 

 shell Conus ttxtilis must have been kept for its beauty as an object of 

 curiosity. 



Method of Obtaining Minute Mollusca.§— The Marquis de Folin 

 describes the following method : — Specimens of the ooze from various 

 shores, bays, and dredgings having been obtained, they should be 

 washed with fresh water in a fine sieve, and then left to dry; if 

 diatoms are being sought for, the results of the filtrations should be 

 preserved, the water decanted, and the deposit left to dry. When 

 dried, the objects should be placed in a box thus formed : the base 

 should be formed of a piece of glass a decimetre square, provided 

 with walls about one centimetre in height which should be fixed to 

 the glass; it will then be possible, as the Marquis points out, to 

 shake the deposit about with safety, while searching for objects of 



* This Journal, ante, p. 551. 



t ' Proc. Acad. Nat. Sci. Phila.,' 1879, p. 16; see 'Nature,' xx. (1879) p. 535. 

 + 'Tiberi, N., ' Le Conchiglie Porapeiane,' Napoli, 1879; see 'Nature,' xx. 

 p. 624. 



§ ' Bull. Soc. Imp. Nat. Moscou,' Iv. (1879) p. 202. 



