PARTULA RADIOLATA. 35 
5 
de stries blanchatres plus intenses sur le dernier tour.” While their figures 18, 19, 
and 20 are undoubtedly gzbba, those numbered 21 and 22 clearly represent the species 
named radiolata by Pfeiffer at the later date specified. Presumably, then, the shells 
denoted a “variety”’ by Quoy and Gaimard were collected by them when they 
visited Guam as members of the Astrolabe expedition and not during their earlier 
visit with the Freycinet expedition; hence the specimens in question did not come 
into the hands of Férussac, who would assuredly have recognized their specific 
- distinctions. 
Garrett visited Guam during the last quarter of the nineteenth century, but 
it is uncertain whether he collected specimens of radiolata as he did of gibba, for the 
evidence on this point is conflicting! Finally Quadras and Rush are named in 
Pilsbry’s Manual as the collectors of distinguishable subordinate forms of this 
species. 
The original description by Pfeiffer, translated in Pilsbry’s Manual (p. 316) 
is as follows: 
Shell subperforate, oblong-tapering, the apex obtuse, thin; sculptured with distant 
impressed spiral lines; pale straw-colored, rayed with darker streaks and brown lines. 
Whorls 5, slightly convex, the last about equal to the spire, base tumid in front. Colum- 
ella short, shortly receding. Aperture obliquely oval, glossy inside, yellow; peristome 
simple, thin, white, expanded, the right margin somewhat straightened, columellar margin 
dilated above, spreading above the umbilicus. Length 19, diam. 10, aperture 9 by 5 
mm. inside. 
Pfeiffer refers to a variety “‘testa carnea, radiis cinnamomeis,” which is a well- 
marked color-form existing in certain localities. No other supplementary diagnoses 
have been given since Pfeiffer’s time, except in the case of the variants mentioned 
by Pilsbry as collected by Quadras and Rush respectively; the last-named is distin- 
guished as P. radiolata rushi1, but in my own opinion it is entitled to the status of 
a color-form only, and not to full varietal standing. 
At this juncture it is well to add the important fact that the parietal tooth of 
many other species is universally lacking in radiolata. Another character of much 
interest is the transparent nature of the egg-capsules, which are entirely devoid of 
calcareous impregnations from their earliest formation. 
In the course of the present investigation, 1,535 adult specimens and 743 
adolescents of radiolata were collected in most but not all of the 39 localities of 
Guam where Partule were secured; the gravid adults yielded 1,909 young and 
3,502 earlier embryos denoted “eggs.’’ ‘Thus there is sufficient material for a 
detailed quantitative description which substantially amplifies the qualitative 
accounts given by earlier authors. This description is concerned with the specific 
characters of radiolata and their variation, and with the collective or colonial diver- 
sification displayed by the associations of different areas, as regards the basic 
qualities of shell structure and coloration as well as the lesser but by no means 
negligible matter of numerical abundance. 
1cf, Smith, loc. c#t., pp. 176, 480. 
