494 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



TROCHOSODON QUINCUNCIALIS, now species 



Plate 70, figs. 7-10 



Description. — The zoarium is orbicular, very convex, subcorneal. 

 The zooecia are arranged in quincunx and form three circular rows; 

 the interzooecial pores are separated. The aperture is buried at the 

 bottom of the peristomie; it is orbicular with a wide, little apparent, 

 distal sinus; the peristome is thin and salient. The base is little 

 convex, with irregular convexities; it is decorated with pores arranged 

 in quincunx and very finely granular; it is bordered with 10-16 salient 

 zooecia. 



Measurements. — Zoarial diameter, 2.5 mm. 



Affinities. — This species differs .from Trochosodon linearis in the 

 arrangement in quincunx of its apertures and in the presence of large 

 convexities on its base. The general surface is finely granulated and 

 of an elegant aspect. 



Occurrence. — D. 5586. Sipadan Island, Sibuko Bay, Borneo; 4° 06' 

 50" N.; 118° 47' 20" E.; 347 fathoms; gy. M.; 6.8° C. 



Cotypes.— Cat. No. 8296, U.S.N.M. 



TROCHOSODON PORCELLANUM, new species 



Plate 70, figs. 4-6 



Description. — The zoarium is a small, denticulated, very convex 

 disk. The zooecia are indistinct, arranged in quincunx, and oriented 

 towards the circumference. The aperture is oval with a small distal 

 sinus; the peristome is incomplete, developed only in the proximal 

 portion; it supports a very small proximal pore. The base bears 8 

 convexities corresponding to the peripheral zooecia. The zoarial 

 surface is finely granulated, brilliant like porcelain with some dis- 

 seminated pores. 



Measurements. — 



» , \lia = 0.12 mm. „ . ^ „ „ n 



Aperture!, n ^ n Zoarium, D = 2.00 mm. 



ito = 0.12 mm. 



Affinities. — This species differs from Trochosodon quincuncialis in 

 its more scattered and less numerous apertures and in its more sepa- 

 rated and fewer decorative granules. 



Occurrence. — D. 5237. Sanco Point, east of Mindanao; 8° 09' 06" 

 N.; 126° 31' 45" E.; 249 fathoms; 8° C. 



Cotypes.— Cat. No. 8297, U.S.N.M. 



TROCHOSODON PARVULUM, new species 



Plate 70, figs. 1-3 



Description. — The zoarium is orbicular, very small, convex. The 

 zooecia are arranged in radial series, two to each series; they bear some 

 sporadic pores. The aperture is oblique, suborbicular, with a little 



