TtEPORT ON THE EAUIOLARIA. 1139 



1. T)-iSsopih')im (etraplecta, n. sp. 



Shell iu the upper half three-sided pyramidal, in the lower half inversely hemispherical, of 

 equal length and breadth. Pores irregular, roundish, in the upper half larger. From the apex 

 there diverge four equal, straight and stout, three-sided pyramidal spmes, one of which is vertically 

 ascending (the horn), the three others oblitiuely descending (the wings). The distal half of the 

 latter is free, whilst the proximal half forms three ribs, enclosed in the shell-wall. Mouth 

 constricted, half as broad as the shell. 



Dimensions. — Shell 0"08 long and broad, horn and wings 0"1 long. 



EaMtat. — Central Pacific, Station 268, depth 2900 fathoms. 



2. Trissopilium lithomditit;a, u. sp. 



Shell ovate, one and one-third times as long as broad. Pores circular, of different sizes, small 

 and numerous. Apical horn very large, straight, cylindrical, vertical, longer than the shell. Three 

 lateral wings shorter, arising from the middle of the shell, conical, curved, divergent. Mouth 

 truncate, two-thirds as broad as the shell. 



Dimemions. — Shell Oil long, 008 broad; horn OlS long, wings 0-09 long. 



Habitat. — Central Pacific, Station 2*71, depth 2425 fathoms. 



Genus 500. Archipilium,^ Haeckel, 1881, Prodromus, p. 427. 



Definition. — A r c h i p i li d a (vel Monocj^-tida triradiata aperta) with three lateral 

 ribs or wings. Mouth truncate, without terminal feet. Apex without horn. 



The genus Archiinlium difi'ers from the nearly allied Trissoptilium, its probal)le 

 ancestral form, in the absence of the apical horn. The three lateral wings of the ovate 

 shell are stout spines. It may also be derived from the similar Scthopilivm by reduc- 

 tion and loss of the cephalis. 



1. Archipilium orthopterum, n. sjj. (PI. 98, fig. 7). 



' Shell ovate, smooth, nearly cylindrical, scarcely broader than the truncate, widely open mouth. 

 Pores numerous, irregular, roundish, of very different sizes. Three lateral wings arising from the 

 middle zone, twice as long as the shell, straight, divergent, stout, cylindrical, longitudinally striped. 

 Dimensions. — Shell O'OS long, O'OG broad; wings 015 long. 

 Habitat. — Central Pacific, Station 272, depth 2(300 fathoms. 



2. Archipilium sigmoptenim, n. sp. 



Shell ovate, smooth, nearly campanulate, of equal length and breadth, one and one-third times 

 as broad as the truncate, sliglitly constricted mouth. Pores scarce, irregularly formed and 



' Arehipiliuvi = Vi'uuoTdhAl hat ; koy^ixChmy. 



