96 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



rim is thick, flat, finely granulated, somewhat enlarged at the base; 

 the opesium is elliptical, very finely denticulated. The ovicell is 

 endozooecial, very small, transverse, smooth, very little salient. The 

 avicularia are placed in the interzooecial angles; they are constant, 

 small symmetrical, triangular, salient, erect. The initial zooecia 

 of a series are often larger; their opesium is deformed, laterally con- 

 stricted in the form of a small bottle. 



Affinities. — The micrometric measurements are quite variable as 

 the least variation of the substratum causes them to change con- 

 siderably. The marginal zooecia are larger and their mural rim is 

 thinner. The ovicell measures 0.10 mm. in height. 



The particular form of the special zooecia well characterizes this 

 charming species. Our specimen was ovicelled in July 1908. 

 Occurrence. — 



D. 5192. Jilantaguan Island, off northern Cebu Island; 11° 09' 



15" N.; 123° 50' E.; 32 fathoms; green S. 

 D. 5478. Tacbuc Point, Leyte; 10° 46' 24" N.; 125° 16' 30" 

 E.; 57 fathoms; Sh. 

 Cotypes.—C&t. No. 7869, U.S.N.M. 



MEMBRENDOECIUM JAPONICUM, new species 



Plate 6, figs. 12, 13 



Description. — The zoarium is unilamellar, free or encrusting shells, 

 bryozoa or pebbles. The zooecia are distinct, separated by a very 

 deep furrow, very little elongated, somewhat elliptical or orbicular; 

 the mural rim is thin, sharp. The internal opesium is suborbicular. 

 The ovicell is large, endozooecial, convex, separated from the zoo- 

 ecium by a prolongation of the mural rim or by a short partition. 

 There are two small fusiform avicularia placed distally, their beak 

 directed toward the zooecial axis. 



Measurements. — 



r, ■ [ho = 0.25-0.30 mm. v ■ [Z2 = 0.65 mm. 



Opesiumi, ZooecmnK, „ .„ 



* \lo = 0.20-0.25 mm. Uz = 0.40mm. 



Structure. — Between the opesia there is a large square area, shallow 

 usually, formed by the frontal of the ovicell. It exists also between 

 the nonovicelled zooecia but it is deeper and very irregular. It is 

 always covered by the ectocyst. 



This species differs from Membranipora tripunctata Waters, 1882 in 

 its nonvinculariform and nonarticulated zoarium, in the absence of 

 a scutum and in the rectangular unpartitioned space. It belongs 

 probably to another family for it forms a very divergent type in the 

 genus. 



The ectocyst is quite transparent and covers also the rectangular 

 area; the opercular valve closes a small apertura. 



