538 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Affinities. — This species differs from Idmonea milneana Smitt, 1872, 

 and from Diaperoecia radicata Kirkpatrick, 1888 in its tubes arranged 

 in alternate fascicles (true Idmonea) and in the large micrometric 

 dimensions (P = 0.26 mm. and not 0.20 mm.). This is a large and 

 vigorous species easily determined with the lens. It differs from 

 Diaperoecia transversalis in which the dimensions are almost as 

 large, in its greater zoarial width and in the alternate arrangement of 

 its fascicles. The colonies are sometimes rose color or red. 



Occurrence. — 



D. 5137. Jolo Light, Jolo; 6° 04' 25" N.J 120° 58' 30" E.; 20 



fathoms; S. Sh. 

 D. 5141. Jolo Light, Jolo; 6° 09' N.J 120° 58' E.; 29 fathoms; 



co. S. 

 D. 5145. Jolo Light, Jolo; 6° 04' 30" N.; 120° 58' 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. (common). 

 D. 5151. Sirun Island, Sulu Archipelago; 5° 24' 40" N.; 120° 



27' 15" E.; 24 fathoms; co. S., Sh. (common). 

 D. 5547. Noble Point, Tulayan Island, vicinity of Jolo; 6° 04' 



45" N.; 121° 20' 20" E.; 114 fathoms. 

 D. 5577. Mount Dromedario, north of TawiTawi Group; 5° 20' 



36"N.;119°58'51"E.;240fathoms;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.; 13° C. 

 D. 5580. Sibutu Island, Darvel Bay, Borneo; 4° 52' 45" N.; 119° 



06' 45" E.; 162 fathoms; br. S., Co.; 13.2° C. 

 Cotypes and plesioty pes. —Cat. Nos. 7375, 8367-8369, U.S.N.M. 



DIAPEROECIA RADICATA Kirkpatrick, 1888 



Plate 82, figs. 1-8 



1888. Idmonea radicata Kirkpatrick, Polyzoa of Mauritius, Annals and Maga- 

 zine of Natural History, ser. 6, vol. 1, p. 83, pi. 9, fig. 2. 



Measurements. — Diameter of peristome, 0.20 mm.; width of 

 branches, 0.75-0.85; diameter of oeciostome, 0.16. 



Variations. — Our specimens are identical with the figure of Kirk- 

 patrick; they are characterized by the expanded form of the peristo- 

 mies, by the oval and accuminate peristome and by the absence of 

 characteristic fascicles. 



The ovicell is elliptical on the branches and flabellate at the 

 bifurcations; it is pierced by a number of variable but always isolated 

 tubes, distant from each other. The oeciostome is small, transverse, 

 orthogonal; it opens perpendicularly to the zoarial plane and often 

 it is visible only in inclining the specimen. 



