1180 THE VOYAGE OF H.M.S. CHALLENGER. 



Suljfamily 1. Archioorida, Haeckel, 1881, Prodromus, p. 427. 



Definition. — C y r t o calj^ id a, with the basal mouth of the shell open (vel Mono- 

 cyrtida eradiata aperta). 



Genus 526. CornuteMa,^ Ehrenberg, 1838, Abhandl. d. k. Akad. 

 d. Wiss. Berlin, p. 128. 



Definition. — A r c h i c o r i d a with conical shell, gradually dilated towards the wide 

 open mouth. Apex armed with a horn. 



The genus CornuteUa is one of the three oldest genera of Polycystina, described 

 by Ehrenberg, in 1838 [CornuteUa, Lithocampe, and Haliomma). He afterwards 

 enumerated, in 1872 and 1875, a large number of fossil and living species, the majority 

 of which, however, belong to other genera of Monocyrtida and Dicyrtida (at least six 

 or seven different genera). We retain here as the true type of the genus the oldest 

 known species: — CornuteUa clathrata, and the nearly allied foi'ms CornuteUa slijlo- 

 phcBna, CornuteUa initra, CornuteUa circularis, &c. The simple conical shell exhibits 

 no distinct trace of an original cephalis, excepting the apical horn; it may have origin- 

 ated either independently, or been derived from Sethoconus, by loss of the cephalis. 



Subgenus 1. CornuteUium, Haeckel. 



Definition. — Axis of the conical shell straight. Pores polygonal, or roundish with 

 polygonal frames. 



1. CornuteUa hexagona, n. sp. (PL 54, fig. 9). 



Shell slender, conical, with straight ontlines. lV>res subregular, liexagoual, gradually increasing 

 in size towards the mouth ; in about ten to twelve longitudinal series, in the upper part very small. 

 Horn slenderly conical, nearly bristle-shaped, long. 



Dimensions. — Shell O^l to 015 long, 0"04 to 0"06 broad. 



Habitat. — Central Pacific, Stations 265 to 274, surface, and at different depths. 



2. CornuteUa sethoconus, n. sp. (PL 54, fig. 10). 



Sliell slender, conical, with undulate outlines. I'ores subregular, hexagonal, gradually increasing 

 in size towards the moutli, in aliout fifteen to eighteen longitudinal series, in the upper j^art circular. 

 Horn small, conical, short. The network is not so delicate as in the preceding similar species. 



Dimensions. — Shell 0-12 to O'lG long, 0-06 to 0-08 broad. 



Habitat. — South Atlantic, Station 332, depth 2200 fathoms. 



' Cornutella=^msXi horn ; diminutive of comu. 



