6i8 



YAICHIRÔ OKA DA : 



This new species is found in abundance in the shallow water of 

 Aburatsubo near Misaki and of Hamajimi in the Miye prefecture, 

 growing on rocks and seaweeds. In the live state, the colour is a 

 beautiful light orange, but fades away into a milky white when pre- 

 served in spirit. The species bsars neither fenestra! nor reteporidm 

 avicularia, a negative fact which seems to constitute a peculiarity of this 



species in contrast to all others of the genus. 



3, Retepova waianabei, n. sp 

 Pl. VIII., fig. s ; textfig 2. 



Zoarium forming a convoluted mass and growing from an incrust- 

 ing disk or from a short peduncle; frequently sending, out from the 

 dorsal surface some calcareous rootlets which reach to the substratum. 

 Fenestrae nearly uniform in size 

 and shape, being oval or ellipti- 

 cal, 2.2 x 0.6 — 2.9 x 0.8 mm. large 

 and about three times as long as 

 wide or longer. Trabeculae re- 

 latively strong, measuring 0.6 — 

 0.8 mm. broad. Zooecia (textfig. 

 2, b) small, elongate, lozenge- 

 shaped, arranged in alternate 

 series, with distinctly raised distal 

 and proximal margins, the ventral 

 wall perforated by three or four 

 relatively small pores in irregular 

 dUtribut on. Zooecial aperture 

 small, suborbicular though inferiòr- 

 ly somewhat narrowed ; operculum 

 (c) nearly orbicular with the lower 

 margin distinctly arched in the middle parts, with submarginai sclerite 

 hich shows a slight incurving on both its lateral limbs somewhat in 



Fig. 2. Retepora waianabei , n. sp. 



a. A few zooecia, two of which are seen 

 provided with ooecia. x 30. 



b. Zooecia with frontal avicularia. x 30. 

 c Operculum, x 200. 



d. Mandible of frontal avicularium with 

 two retractor muscles, x 200. 



