AMPULLARIA. 413 
the length of the aperture, instead of 0°84 and 0°59, as in the typical A. malleata. The 
measurements given by Canon Tristram himself, however, by the same reckoning are 
0°94 for the whole shell as in the specimen examined by me, but 0°84 for the aperture. 
Fischer and Crosse were probably misled by the words “ anfractus ad suturam acute 
angulati” to think it a very different species, distinct by a sharp angular spiral line or 
keel near the suture; but the specimen now before me proves clearly that these words 
mean only that the outer wall of each whorl joins in an acute angle to the wall of the 
preceding whorl, the inner cavity of each whorl being acutangular above, which is 
characteristic of all forms of A. flagellata. 
Var. tristrami. (Tab. XXII. figg. 1, 12.) 
Pomus columbiensis, Tristram, P. Z. S. 1863, p. 4147. 
Ampullaria malleata, Fisch. & Crosse, loc. cit. p. 235, t. 46. fig. 2 (specimen from Cahabon) * 
Ampullaria tristrami, Fisch. & Crosse, loc. cit. p. 234 (part.) ”. 
Not quite so large as the var. gigantea, and comparatively a little broader, but with the superficial suture of the 
species ; surface shining, with vertical stric and very few slightly malleated impressions; yellowish-green, 
the vertical striz somewhat paler, and therefore more conspicuous; a broad pale zone at the suture, well 
defined on the last whorl; some narrow spiral bands, two or three of which are usually placed near 
together, on the lower half of the last whorl. Peristome a little expanded below, yellow, with a chestnut- 
brown stripe inwards ; interior of the aperture brownish-violet, paler towards the peristome. 
Long. 64, diam. 58; apert. long. 47, diam. 33 millim. 
Hab. N. Guatemata: Lake of Peten (Salvin 2" 2°), Cahabon (Sarg 8). 
Salvin’s original specimen now before me does not agree with Philippi’s or Reeve’s 
A. columbiensis, but is a variety of A. flagellata, nearly allied to the var. gigantea. 
Fischer and Crosse’s figure of their Cahabon shell coincides so well in size, shape, and 
external colour with Salvin’s specimen that I have no hesitation in referring it to the 
var. tristrami; only the interior of the aperture is conspicuously banded, as is often 
the case in not quite full-grown individuals, in which the last layer of the calcareous 
shell is still wanting. 
They also give 28 Panzos and Lake Yzabal (Bocourt) as localities for A. malleata, but 
whether the specimens from these places really belong here I am unable to say. 
There is some difficulty regarding the name of this variety. Fischer and Crosse not 
having seen Salvin’s specimen, referred it to Reeve’s A, columbiensis (1856); but as this 
name was preoccupied by Philippi (1801) they gave it a new one, copying, however, 
the description from Reeve. As their name clearly refers to Tristram’s shell, and could 
not be applied to Reeve’s A. columbiensis from Veraguas, it is best to adopt it. 
Var. guatemalensis, 0. (Tab. XXII. figg. 11, 11 4.) 
Ampullaria malleata (Jonas), Fisch. & Crosse, loc. cit. p. 234 (part.), t. 45. fig. 1, t. 46. figg. 1,2. 
Somewhat broader, with more prominent, pointed spire and slightly deeper suture, Peristome generally more 
narrowly expanded. Size sometimes large. No or very few malleated impressions. 
a. Long. 91, diam. 78; apert. long. 634, diam. 423 millim. 
ee es 54, , 32 3 
