— 37 ~ 



übrigens hierzu das weiter unten bei den Spongopyliden gesagte. 

 Das Pylom ist von kleinen, gleich großen Zähnchen umrahmt. 

 Durchmesser der Schale : 0,087 : 0,126. 

 „ Poren: 0,004—0,015. 

 „ „ Balken : ca. 0,004. 



des Pyloms: 0,043. 

 Länge der Zähnchen desselben: 0,004. 

 Dicke „ „ „ 0,002. 



Station 271, Boden. 



Genus 2: S toma todiscus, Haeckel. 



Definition. — Porodiscida without chambered arms and radial 

 spines on the margin of the circular or elhptical disk, but 

 with two large, opposite, marginal oscula, or openings sur- 

 rounded by a Coronet of spines. 

 In der oben begründeten Weise modifiziert lautet diese 



Diagnose : 



Ommatodisciden mit 2 randständigen Pylomeu, welche sich 



an beiden Polen der Hauptachse der runden oder elhptischen 



Scheibe gegenüberstehen. 



1. Stomatodiscus amphistomus, Haeckel. 



Disk circular, with three concentric rings of equal breadth 

 around the central Chamber. Pores irregulär, roundish, about 

 two on the breadth of each ring. Surface of the lenticular shell 

 spiny. On two opposite points of the margin a large osculum, 

 three to four times as broad as the central Chamber, armed with 

 a Coronet of strong pyramidal spines of ditferent length, the 

 longest equal to the radius of the disk. 



Dimensions. — Diameter of the disk (with three rings) 0,12 ; 

 breadth of each ring 0,016; pores 0,004. 



Habitat. — South Pacific, Station 302, depth 1450 fathoms, 



2. Stomatodiscus osculatus, Haeckel (Report, Plate 48, Fig. 8). 

 Disk elliptical, nearly twice as long as broad, with three con- 

 centric rings around the elliptical central Chamber, one piercing 

 radial beam in the main axis, the other beams interrupted. Sur- 

 face of the shell with scattered small thorns. Pores very irre- 

 gulär, roundish, partly aggregated in groups of four to eight 

 smallei' porules. On both poles of the main axis a large ellip- 



