324 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



present and the following species complete the series but we have 

 also some incomplete specimens of another species dredged to the 

 north of Tawi Tawi. 



This species is very repugnant in the variation of its ovicells and 

 unexpected arrangement of its zooecia. The beak of the avicu- 

 larium is turned toward the base and has a pivot. 



Biology. — It is rare to find zooecia of this size. Certain species 

 of Petraliidae and of Hippopodinidae alone reach such size. Gigan- 

 tism in the Bryozoa as in other animals is not a proof of longevity. 

 Our specimens were dead. 



Occurrence. — On Tridacna from an unknown Philippine locality. 



Eolotype.— -Cat. No. 8366, U.S.N.M. 



HIPPOMENELLA POROSA, new species 



Plate 38, figs. 2, 3 



Description. — The zoarium encrusts cellepores and debris. The 

 zooecia are distinct, separated by a shallow furrow, very large, elon- 

 gated, elliptical, swollen; the frontal is little convex, ornamented 

 with a double row of large areolar pores and with thick costules 

 smooth in the vicinity of the aperture. The aperture is large and 

 suborbicular, with a smooth vestibular arch; the peristome is thin 

 and little salient. The ovicell is very large, convex, imbedded in the 

 distal zooecium, ornamented with large costules directed toward a 

 median knob; the two areas are deep, triangular, and limited by the 

 costules; the orifice is a narrow slit placed above the aperture. The 

 avicularia are small, triangular, transverse, scattered among the pores. 



Measurements. — 



A . \ha -0.20-0.25 mm. v^-^Lz^lM mm. 



Apertura , n nn n nm Zooecium 



\la =0.20-0.25 mm. U2 -0.75 mm. 



Affinities. — This superb species is easily distinguished from Hippo- 

 menella repugnans by its small avicularia and the unusual richness of 

 its ornamentation. At the base of the ovicell there are two large 

 hollow spines. Only the figured specimen has been found. 



Occurrence.— D. 5577. Mount Dromedario, Tawi Tawi; 5° 20' 36" 

 N.J 119° 58' 51" E.; 240 fathoms; coarse sand. 



Eolotype.— -Cat. No. 8466, U.S.N.M. 



Genus HIPPODIPLOSIA Canu, 1916 



HIPPODIPLOSIA(?) BACULINA, new species 



Plate 36, figs. 7, 8 



Description. — The zoarium is free and formed of small rods con- 

 taining 4 longitudinal rows of zooecia. The zooecia are distinct, 

 separated by a deep furrow, little elongated, rectangular; the frontal 

 is quite convex, very thick, granular, covered by small expanded 



