HETEROCYCLUS. DIADEMA. 
55 
subirregulariter circulare, marginibus Icviter incrassatis. — 
Operculum subcirculare, tenue, cartilagineo - corneum , infra 
planiusculum, supra arctispirum, medio concaviusculum; nucleo 
centrali; margine externo anfractuum prominulo, libero, ad 
terminum anfr. ultimi attenuato.“ 
Heterocyclus (novum genus) Cross# in Journ. Conch. XX. 1872. p. 156. 354. 
„Genus testa turrita a Cyclophoris discrepans et operculi 
forma peculiari inter genera Cyclophorum et Pterocyclum quasi 
medium, sed ab utroque bene distinguendum“. (Cr.) 
i. H. Perroquini Crosse, f 
„ T. perforata , breviter scalariformi - turrita , sublaevis, 
haud nitens, tenuiuscula, subtranslucida, sordide luteo-albida ; 
spira turbinato-turrita, apice obtusulo; sutura impressa; anfr. 
4 convexi , sensim accrescentes , ultimus valde descendens, 
solutus, liber; apertura subirregulariter circularise intus con- 
color; peristoma simplex, marginibus leviter incrassatum. — 
Operculum arctispirum, albido-luteum ; anfr. 4 sensim accres- 
centes, margine externo prominulo, libero. — Long. 4y 2 , 
diam. maj. 2 1 / A mill. Apertura l 1 /^ mill, longa, 1 lata.“ (Cr.) 
Heterocyclus Perroquini Crosse in Journ. Conch. XX. 1872. p. 156. 355. 
t. 16. f. 6. 6 a. 
Habitat „Baie du Sud“ Novae Caledoniae meridionalis 
(Perroquin). 
XIV. Diadema Pease. 
„Testa globoso-turbinata, umbilicata; peristoma continuum, 
rectum, liberum aut vix adnatum, simplex, subcirculare. 
Operculum subcartilagineum, elevatim spiral! ter lamella- 
turn, intus concavum, basi late reflexum.“ (Pease.) 
Diadema (novum genus) Harper Pease in Amer. journ. conch. IV. 1868. 
p. 157. 
Garrettia „Pease“ Patel Catal. 1873. p. 17. 124: genus Realieorum. 
— 0. Semp. in Mus. Godeffr. cat. V. p. 100. 
Pterocycli spec. Pease antea. 
Species : 
i. D. parva (Pterocyclos) Pease, f 
„T. turbinata, solida, fusco-rufescens, longitudinaliter te- 
nuissime striata, apice acuto, late umbilicata; anfr. 4, ultimo 
