BRYOZOA OF THE PHILIPPINE REGION 425 



D. 5577. Mount Dromedario, north of Tawi Tawi; 5° 20' 36" N. ; 



119° 58' 51" E.; 240 fathoms; crs. S.; 12.4° C. 

 D. 5579. Sibutu Island, Darvel Bay, Borneo; 4° 54' 15" N.; 



119° 09' 52" E.; 175 fathoms; fine S., Co. 

 Plesioty pes. —Cat. Nos. 8237-8241, U.S.N.M. 



HOLOPORELLA ERECTOROSTRIS, new species 



Plate 61, figs. 1-6 



Description. — The zoarium is massive, irregular, globular, free, or 

 fixed. The zooecia are distinct, little erect, almost buried; the 

 frontal is smooth, convex, granular on the zoarial margins. The 

 apertura is semielliptic, transverse, with two small denticles placed 

 on the lower third of the anter and a small denticle placed on the 

 poster. There are 3 or 4 small distal spines. The operculum is very 

 fragile and of ordinary form. The avicularian umbo is small, little 

 salient, placed in the vicinity of the aperture; it is very long on the 

 deep zooecia and can be transformed sporadically into real columns. 

 The interzooecial avicularia are numerous, rather large, oval, curved; 

 the beak is free, quite raised, suberect and clearly detached from the 

 adjacent zooecia. The mandible is spathulate. The ovicell is globu- 

 lar, smooth, transverse, hyperstomial and generally placed on the deep 

 zooecia. 



Measurements. — 



. \ha = 0.10 mm. 1 Length of the larger avicularia = 



Apertura {Za= 0.12-0.14 mm.] 0.40 mm. 



Affinities. — This species belongs to the tridenticulata group. How- 

 ever, it differs from Holoporella tridenticulata Busk, 1881, in its much 

 smaller and less apparent oral armature, in its smaller oral dimensions 

 and in the presence of numerous free, curved avicularia. It differs 

 from H. serratirostris MacGillivray, 1884, in its little salient beak, 

 in the presence of 3 or 4 small distal spines, in the free and salient 

 beak of the interzooecial avicularia and in the possible transformation 

 on the deep zooecia of the avicularian beak into small pillars or col- 

 umns. The latter are never so large nor so frequent as in Holoporella 

 pilaejera, new species. 



Biology. — The colonies measure more than 1 cm. in diameter. They 

 are free and fixed to corals, Serpulae, shells, foraminifera, Retepores, 

 and nullipores. Their color is brown. Many of our specimens were 

 living and were in reproduction from February 19 to July 29, so it is 

 probable that the species was in continuous reproduction. It is 

 associated with Holoporella serratirostris, but its geographical dis- 

 tribution in the Philippine region appears to be more restricted. 



