1166 THE VOYAGE OF H.M.S. CHALLENGER. 



2. Cyrtophormis cerostatica, n. sp. (PL 52, figs. 2, 3). 



Shell balloon-shaped, subspherical, with twenty smooth meridional ribs, alternating with twenty 

 longitudinal rows of circular pores, of tlie same breadth as the bars. Peristome constricted, about 

 half as broad as the shell. 



Dimensions. — Shell 0-09 long, 0-07 broad ; mouth 0-03 broad. 



Habitat. — Central Pacific, Station 266, depth 2750 fathoms. 



3. Cyrtophormis spiralis, n. sp. (PI. 51, fig. 9). 



Shell ovate, one and a half times as long as broad, with twenty spirally convoluted, elegantly 

 denticulated ribs, alternating with twenty spiral rows of small circular pores, of about the same 

 breadth as the bars. Peristome constricted, very small, only one-seventh as broad as the shell. 



Dimensions.- — Shell 0"1 long, 0'07 broad ; mouth O'Ol broad. 



Hahitat. — West Tropical Pacific, Station 225, depth 4475 fathoms. 



4. Cyrtojyhormis tahulata (PI. 79, fig. 2). 



Shell urceolate and tabulate, twice as long as broad, with twenty-five to thirty denticulated 

 longitudinal ribs, crossed by twenty to twenty-four transverse rings. Pores therefore regularly 

 disposed in longitudinal and transverse rows ; each pore circular, with a square frame. Peristome 

 constricted, scarcely half as broad as the shell. 



Dinunsums. — Shell 0'2 long, O'l broad ; mouth 0'04 broad. 



Habitat. — Soixth Pacific, Station 300, depth 1375 fathoms. 



Genus 517. Halip>hormis^ Elirenberg, 1847, Monatsber. d. k. preuss. *Akad. 

 d. Wiss. Berlin, p. 54 (sensu mutato). 



Definition. — A r c h i p li o r m i d a (vel Monoeyrtida multiradiata aperta) with 

 numerous radial ribs in the wall of the campanulate shell, prolonged into free terminal 

 feet. Apex with a horn. 



The genus Hcdiphormis (with an ajiical horn) and the following Archipihormis 

 (without a horn) comprise those Archiphormida in which the open mouth is more or less 

 constricted and surrounded by a coronet of radial feet, as terminal prolongations of the 

 radial ribs of its wall. The few forms, upon which Ehrenberg originally founded the 

 genus Hali2)hormis, are partly not recognisable, partly belong to other genera. We 

 therefore give here a new definition of the genus, as stated in my Prodromus, 1881, 

 p. 428. 



^ Haliphormis =Sea-ba,sket ; «7if, (fo^/iig. 



