BRYOZOA OF THE PHILIPPINE REGION 403 



proximal border bears a rather wide, semicircular rimule; the peri- 

 stome is thin, somewhat salient, complete. 

 Measurements. — 



. I ha -0.10 mm. „ . \Lz -=0.65-0.85 mm. 



Apertura , _ , _ _ Zooecia , n _ A 



* \ la -=0.10 mm. [ Iz =0.30 mm. 



Affinities. — This new species differs from Parmularia cylindrica in 

 its concave frontal (and not convex) and from Parmularia elongata, 

 in its much smaller micrometric measurements. Only the figured 

 specimen has been found. 



Occurrence. — D. 5574. Simaluc Island, north of Tawi Tawi; 5° 30' 

 45" N.; 120° 07' 57" E.; 340 fathoms. 



Holotype— Cat. No. 8212, U.S.N.M. 



Family PHYLACTELLIDAE Canu and Bassler, 1917 



Genus PERIGASTRELLA Canu and Bassler, 1917 



We created this genus in 1917 before we had received the later 

 work of Levinsen. We are now able to complete our text figure 

 from a study of a recent typical species. 



To the list of recent species given by us in 1920 it is necessary to 

 add the following: 



Perigastrella (Escharella) abyssicola Norman, 1868. 

 Perigastrella (Discopora) stenostoma Smitt, 1871. 

 Perigastrella (Lepralia) microstoma Norman, 1868. 

 Perigastrella (Escharella) indivisa Levinsen, 1916. 

 Perigastrella (Escharella) macrodonta Levinsen, 1916. 



All the recent species inhabit the arctic regions or the northern 

 part of the temperate zone. Perigastrella contracta Waters, 1899, 

 from Madeira is a very aberrant type for which it may become 

 necessary perhaps to form a special genus. The 14 known fossil 

 species in Europe as well as in America, are on the contrary species 

 of the tropical zone or of the southern region of the temperate zone. 

 There has therefore been a regular emigration from the south toward 

 the north of all the species of the genus and this migration is the 

 cause of the specific differentiations. The theory which takes into 

 consideration the contraction of the equatorial zone as the cause of 

 these differences is therefore quite false for the bryozoa, for we can 

 cite other examples. 



PERIGASTRELLA OVALIS, new species 



Plate 56, figs. 1, 2 



Description. — The zoarium encrusts pebbles. The zooecia are 

 distinct, separated by a very deep furrow, large, elongated, oval; the 

 frontal is quite convex, formed by a smooth or very finely granulated 



