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each spot of land suitable to them will contain distinct species which 

 are not to be found elsewhere. $. pisum is a remarkable exception. 

 That shell occurs in the Back Woods or highest mountains in the 

 north of Manchester; at Porus, say ten miles "crow-fly" distance 

 on the east border of Manchester ; at Moreland and " Bull dead" 

 in Manchester, say about the same distance south, near the western 

 border : and again it is found at Accompong Town in St. Elizabeth's 

 parish, at (say) twenty-five or thirty miles to the west. And it is 

 curious to observe, that, taking Manchester back woods as the focus, 

 I have collected and received shells from many intermediate spots 

 between it and Porus and Moreland, and Bull dead and Accompong 

 town, without getting one St. pisum, although many shells equal or 

 smaller in size of other genera and species. But take any other of 

 the Stoastomidce, and probably you will search for it in vain outside of 

 a circumference of three-fourths of a mile from the spot where it first 

 was found. Each such spot will contain probably as many as four 

 or six or seven species ; but to that spot all those species are confined. 

 In the following descriptions it wilkbe seen that the habitat of six 

 species is certainly " Peace River : " and that that of eight species 

 is as certainly Yallahs Hill. That latter I have personally explored ; 

 one of my residences was near by, and I repeatedly visited it ; and I 

 have no hesitation in saying that none of those eight species are to 

 be found at half a mile either way. There are hundreds of spots 

 of this kind in the island never trodden by human foot, and there^ 

 fore there is no knowing how many Stoastomidce and other minute 

 shells might yet be found, or how many of other genera, from large 

 to small, may yet be added to the terrestrial conchology of Jamaica. 

 The number of unique specimens in my cabinet tells us this truth, 

 I having been a collector in situ for years by myself or my black 

 deputies, who are rarely to be bribed into a repetition of a visit to a 

 strange and unwelcome spot. 



I must here record my great thanks to my friend Dr. S. Livesay 

 for the personal assistance he has afforded me with some of these 

 troublesome shells ; but more especially, not only for the loan of his 

 microscope throughout the labour, but for his most ingenious con- 

 trivances, which have been of the greatest help in the examination 

 and measurement of shells, enabling me, by aid of one, to examine 

 all parts by a rotatory motion, and at the same time to readily compare 

 one shell with another ; and by aid of another, on the sliding-scale 

 principle, to measure by the thousandth part of an inch with the 

 nicest accuracy and with the greatest facility. Future describing 

 conchologists would do well to make inquiries of that gentleman. 



In order to give a clearer understanding of my descriptions, it is 

 well to state how I have proceeded to examine the shell. Dr. Live- 

 say's apparatus consists of a plate on which a battery (as it were) of 

 large pins may be placed in grooves, and kept firm by an upper plate, 

 moveable at one end, so as to admit of removing them when required, 

 and fixed at the other by a hinge. These pins are revolved in their 

 grooves by the fingers, there being a small piece of rounded cork 

 stuck on the point of the pin to lay hold of. The shell is gummed 



