HETEROCYCLUS. DIADEMA. 55 
subirregulariter circulare, marginibus leviter incrassatis. — 
Operculum subeireulare, tenue, cartilagineo - corneum, infra 
planiusculum, supra arctispirum, medio concaviusculum; nucleo 
central; margine externo anfractuum prominulo, libero, ad 
terminum anfr. ultimi attenuato.* 
Heterocyclus (novum genus) Crosse in Journ. Conch. XX. 1872. p. 156. 354. 
Genus testa turrita a Cyclophoris discrepans et opereuli 
forma peculiari inter genera Cyclophorum et Pterocyclum quasi 
medium, sed ab utroque bene distinguendum*. (Cr.) 
1. H. Perroquini Crosse. 1 
».1l. 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 circularis, intus con- 
color; peristoma simplex, marginibus leviter incrassatum. — 
Opereulum aretispirum, albido-luteum; anfr. 4 sensim accres- 
centes, margine externo prominulo, libero. — Long. 4!/,, 
diam. maj. 2!/, mill. Apertura 1!/, mill. longa, 1 lata." (Cr.) 
Heterocyclus Perroquini Crosse in Journ. Conch. XX. 1872. p. 156. 355. 
vio as fe a] ce 
Habitat ,Daie du Sud* Novae Caledoniae meridionalis 
(Perroquin). 
XIV. Diadema Pease. 
esta globoso-turbinata, umbilicata; peristoma continuum, 
rectum, Brun aut vix adn simplex, subcirculare. 
Operculum subeartlagineum, elevatim spiraliter lamella- 
tum, intus concavum, basi late reflexum.* (Pease.) 
Diadema (novum genus) Harper Pease in Amer. journ. conch. IV. 1868. 
p. 157. 
Garrettia , Pease* Pütel Catal. 1873. p. 17. 124: genus Realieorum. 
— O. Semp. in Mus. Godeffr. cat. V. p. 100. 
Pterocycli spec. Pease antea. 
Species: 
1. D. parva (Pterocyclos) Pease. 1 
»l. turbinata, solida, fusco-rufescens, longitudinaliter te- 
nuissime striata, apice acuto, late umbilicata ; "anfr. 4, ultimo 
