120 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



D. 5162. Tinagta Island, Tawi Tawi Group; 5° 10' N.; 119° 



47' 30" E.; 230 fathoms; S. brk., Sh. crs. 

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



09' 15" N.J 123° 50' E.; 32 fathoms, green S. 



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



119° 09' 52" E.; 175 fathoms, fine S., co.; 13, 2° C. 



Torres Strait, Station 186, 8 fathoms (Busk); Albany Pass, 



Somerset, N. Queensland, 10 fathoms (Kirkpatriek). 



Plesiotypes. —Cat. Nos. 7918-7921, U.S.N.M. 



Family ARACHNOPUSIIDAE Jullien, 1888 



Orifice trapezoidal; frontal perforated by pores irregularly arranged 

 in the place of which origelles (tremopores) can not be distinguished 

 on examples decalcified and tinted with the picrocarminate of 

 ammonia; operculum pellucid, very thin, quite difficult to see and 

 of doubtful existence. Ancestrula membraniporoid, spiny. (Trans- 

 lation after Jullien.) The ovicell is hyperstomial always closed by 

 the operculum. The zooecia are entirely adjacent. The frontal is 

 a pericyst with large pores arranged above a membranous ectocyst. 

 The ectocyst, therefore, is buried under the frontal. 



Levinsen, 1909, writes that the frontal is formed by branched 

 projections which are solid and originate from the lateral margins. 

 According to Waters, 1903, there are oral glands. The term peripore 

 is applied to the salient collar which surrounds the large pores of 

 the pericyst. 



In order not to always change the nomenclature we follow here 

 the same rule as for the Hiantoporidae and accept Jullien's family. 

 The true nomenclature of all these forms can be definitely established 

 only with the knowledge of their larvae. 



To the genus AracJinopusia Jullien, 1888, now better known, we 

 have added the genus Exechonella which has a great geological dis- 

 tribution. The genus AracJinopusia has been described and illus- 

 trated by the present writers in 1920 (North American Early Ter- 

 tiary Bryozoa, p. 311). 



Genus EXECHONELLA Canu and Bassler, 1927 



The pores of the pericyst are large, orbiculur, marginated. A 

 peristomie very much thickened surrounds an orifice closed by a 

 true operculum. The ectocyst is hidden under the frontal. The 

 microscopic study of the frontal having indicated to us that it is 

 not formed by the fusion of hollow spines, causes us to ally this 

 genus with AracJinopusia Jullien, 1888. It differs from it in the 

 presence of an operculum and of large orbicular, frontal pores. We 

 are still unfortunately ignorant of the nature of the ovicell. 



