306 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



broad rimule; the peristome is olocystal and nonsalient. Near the 

 aperture is a very small avicularium placed on the median zooecial 

 axis. The ovicell is very large, embedded in the distal zooecium, 

 closed by the operculum and covered by the tremocyst as the frontal. 

 The ancestrula is a very small zooecium. Frequently a large inter- 

 zooecial avicularium is present. 

 Measurements. — 



Anertura^ ^°' 14 mm * Zooecial 2 ^ - 44 -°- 54 mm - 



F Ua =0.16 mm. \lz =0.26-0.30 mm. 



Structure. — Frequently there is a separating thread at the bottom 

 of the furrow. The orifice of the ovicelled zooecia is larger and 

 measures 0.15 by 0.19 mm. The operculum is elongated contrary- 

 wise to the apertura; it bears a peripheral sclerite, two broad lateral 

 bands and two lucidae at the level of the cardelles. The difference 

 from typical Schizomavella is little apparent. The frontal and dorsal 



Q O O O 



A B 



Fig. 129. — Opercula, X85, of Schizomavella (Metro per iella) 



A, B. S. ovoidea, new species. Two opercula, X85. C.-E. S. lepralioides, new 

 species. Opercula of ovicelled (C) and ordinary zooecia (D, E.) 



structures are also identical with those of Emballotheca and of 

 Schizomavella. 



Biology. — We have already noted a large analogous avicularium in 

 Metroperiella avicularis Canu and Bassler, 1920, a fossil from the 

 Eocene (Jacksonian). Our living specimens show that they were in 

 reproduction and fixation during all the month of February, 1908 

 (36 meters). This species frequents shallow waters and sandy, coral- 

 line and shelly bottoms. 

 Occurrence. — 



D. 5134. Balukbaluk Island, Sulu Archipelago; 6° 44' 45" N.; 



121° 48' E.; 25 fathoms; fine S. 

 D. 5137. Jolo Light, Jolo; 6° 04' 25" N.; 120° 58' 30" E.; 



20 fathoms; S., Sh. 

 D. 5141. Jolo Light, Jolo, Sulu Archipelago; 6° 09' N.; 120° 58' 



E.; 26 fathoms; co. S. 

 D. 5144. Jolo Light, Jolo; 6° 05' 50" N.; 121° 02' 15" E.; 19 



fathoms; co., S. 

 D. 5145. Jolo Light, Jolo; 6° 04' 30" N.j 120° 59' 30" E.; 23 



fathoms; co., S., Sh. 

 D. 5147. Sulade Island, Sulu Archipelago; 5° 41' 40" N.; 120° 

 47' 10" E.; 21 fathoms; co., S., Sh. 



