The Hon. E. Chitty on the Stoastomidse. 69 



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 

 on to the pin's head, so that the plane of aperture is parallel to the 

 length of the pin, and the axis of the shell at right angles v^^ith it. 

 In this position the operculum, jf there, or if not, the inside of the 

 aperture, and also the apex and umbilicus, and indeed all parts of 

 the shell, except the point of attachment, can be brought under the 

 microscope by revolving the pin. 



Next, let me explain any new terms I may have used. In speak- 

 ing of "above " or *' below," I always consider the apex the upper- 

 most, and the umbilicus the lowermost part. In speaking of *' right " 

 or *' left," the outer edge of the aperture is considered to be on the 

 right hand. 



In pursuing the examination, we give in succession Form and Co- 

 lour. Those two are manifest. Sculpture : we commence by describing 

 the sculpture of the last whorl, and calculate from below the suture 

 downwards towards the umbilical region at about a quarter from the 

 aperture, or the last quarter or third of the last whorl. Spiral 

 carince are sculptured raised lines, transverse to the axis or column 

 of a shell. The spire and its outlines are self-evident. Whorls are 

 counted from the aperture upwards ; 'from that part to where it is 

 opposite or attached to, what is termed, the body-whorl, forms one 

 whorl, and so on upwards, the whole, half, third, or quarter being 

 determined by the exact termination of the appearance of a suture 

 at the nuclear apex. The aperture, or moutli, though not audibly, 

 speaks its own shape, &c. Labrum in Stoastoma is the edge of the 

 right-hand portion of the aperture, extending from the suture, as it 

 were, above, round on the right, till it finishes its curve below ; the 

 labium being the almost straight part on the left. Labral and labial, 

 coined words, refer to those parts of the edge of the aperture, &c. 



