48 PROCEEDINGS OF THE NATIONAL MUSEUM vol.. 76 



Family MECYNOECIIDAE Canu, 1918 

 Genus MICROECIA Canu, 1918 



MICROECIA TUBIABORTIVA, new species 



Plate 8, Figures 6, 7 



Description. — The zoarium incrusts shells. The primitive Beren- 

 icea form gives rise to palmate or rectilinear fronds. The tubes 

 are little distinct, very little convex, smooth, irregularly arranged; 

 the peristomies are very short and oblique. The orifice is orbicular; 

 the peristome is thin. Aborted tubes, visible or invisible, form 

 irregular spots on the colonial surface. The ovicell is small, orbic- 

 ular, little convex, perforated by a small oeciopore. 



Measurements. — Diameter of orifice, 0.10 mm. ; diameter of peris- 

 tome, 0.14 mm.; distance of orifices, 0.44 mm. (variable) ; separation 

 of orifices, 0.16-0.24 mm. 



Affinities. — The colony is very irregular in appearance because the 

 fronds rising from the primitive Berenicea form are irregular in 

 dimensions. This mode of ramification of the branches is rather rare 

 and very well characterizes this species. 



The large, smooth, trregular spaces distributed between the tubes 

 on the zoarial surface are occupied in reality by aborted tubes. They 

 are altogether invisible or simply indicated by salient threads or, 

 more rarely, visible but closed by a lamella. We are absolutely igno- 

 rant of the utility of this structure. 



Occurrence. — Galapagos Islands, D. 2813. 



Eolotype..— Cat. No. 8524, U.S.N.M. 



Family PLAGIOECIIDAE Canu, 1918 

 Genus PLAGIOECIA Canu, 1918 



PLAGIOECIA LACTEA Calvet, 1903, variety 



Plate 11, Figures 7, 8 



1903. Diastopora lactea Calvet in Jullibn and Calvet, Eryozoaires provenant 



des Campagnes de I'Hiroiidelle, p. 163, pi. 18, fig. 4 (Gulf of Gascogny, 



43° 37' N. ; long. 90° 27' 300 meters, on hydroids). 

 1907. Diastopora lactea Calvet, Eryozoaires des expeditions scientifiques du 



Travailleur et du Talisman, p. 466 (Cape Spadel, Morocco, 717 meters 



on LopJiohelia) . 



Measurements. — Diameter of orifice, 0.08 mm.; diameter of peris- 

 tome, 0.10-0.12 mm.; distance of tubes, 0.40-0.50 mm.; external sepa- 

 ration of tubes, 0.40-0.50 mm. 



Affinities. — Our specimen differs from those from the Gulf of Gas- 

 cogny in the less numerous cells on the border and 2n the presence of 



