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



14. Siphonospheera pipetta, n. sp. (PL 6, fig. 3). 



Shell more or less irregularly roundish or subspherical, occupied in part by very small pores, 

 in part by very large cylindrical tubules, inflated in the middle. Number, form, and size 

 of the tubes very irregular; commonly there are five to ten, half as long or as long as the 

 shell radius ; their inner and outer aperture about half as broad as their inflated middle part ; 

 three to nine times as broad as the pores. A very irregular and variable species. 



Dimensions. Diameter of the shell 01 to 015, of the pores O'OOl to 0'005, of the tubules 

 0-015 to 0-03 ; length of the tubules 0'03 to 0'08. 



Habitat. North Pacific, Stations 242 to 253, surface. 



Genus 37. Mazosphcera, 1 Ehrenberg, 1860. 



Mazosphcera, Ehrenberg, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 833. 



Definition. Collosphaer ida with simple shells, the pores of which are pro- 

 longed into external simple radial tubuli with solid wall ; outer mouth of each tubulus 

 armed with a single tooth. 



The genus Mazosphcera is intermediate between Siphonospheera and Odontosphcera, 

 agreeing with the former in the tubular prolongation of the pores, with the latter in 

 the possession of a single large protective tooth on the outer opening. 



1. Mazosphcera hippotis, n. sp. (PI. 5, fig. 8). 



Shell spherical, with circular pores of irregular size and distribution, scarcely half as broad as 

 the bars; fifteen to twenty on the half meridian of the shell. Between them, irregularly 

 distributed, a variable number (ten to fifteen) of short cylindrical radial tubules, about twice as long 

 as broad, and half as long as the shell radius. Mouth of the tubuli obliquely truncated, having 

 on one side a strong acute tooth. 



Dimensions. Diameter of the shell Oil to 012, of the pores 0'002 to 0'004, of the bridges 

 0-006 to 0-009 ; length of the tubuli 0'03, breadth of them O'Ol to O'Olo. 



Habitat. North Pacific, Station 253, depth 3125 fathoms. 



2. Mazosphcera lagotis, n. sp. (PI. 5, fig. 9). 



Shell spherical, with circular pores of irregular size and distribution, about as broad as the 

 bars ; twelve to sixteen on the half meridian. Between them, irregularly distributed, a variable 

 number (eight to twelve) of long, cylindrical, curved tubules, three to six times as long as broad, and 

 about as long as the shell radius ; their external mouth lateral, obliquely truncated, ovate, having 

 on one side a strong conical tooth. 



