624 



YAICHIRÔ OKADA : 



are provided with an elongate subtriangular mandible pointed and 

 curved at the extremity. All avicularia of the species have a small 

 and inconspicuous avicularian gland of a globular shape and are 

 furnished with two retractor muscles attached to the lower margin of 

 mandible. 



i2. Metepora kinoshitai, n. sp. 

 Pl. VIII., fig. 7 ; textfig, 4. 



Zoarium erect, sometimes slightly decumbent, spreading in a plane 

 from a common peduncle which expands below into a non-celliferous 

 base for attachment. Branches numerous, dichotomous, dorsoventrally 

 flattened, broadest in basal parts, non-reticulating, conically rounded 

 at the free end. Zooecia rhomboidal, alternately disposed ; the ventral 

 surface irregularly nodulous, sparsely perforated by pores. Zooecial 



aperture small, nearly semi- 

 circular, the curved lower 

 margin with a distinct labial 

 fissure. In the younger zooecia 

 (textfig. 4 a.) and also in those 

 situated on the lateral sides of 

 branches, the marginal wall of 

 the aperture forms, on each 

 side and at the upper end of 

 the cell margin, an angular 

 process bearing a small spine 

 at the apex. Operculum broad- 

 ly semicircular, with moderate- 

 ly thick sclerite (c). Avicularia 

 immersed, present in three 

 kinds : small, medium sized, 

 and large. The small avicu- 

 larium (e) is the commonest, 



Fig. 4. 



Yig. 4. Retepora kinoskitai, n. sp. 



a. Ventral view of zooecia. X30. 



b. Zooecium with ooecium. X30. 



C Operculum showing two opercular glands. 



X200. 



d. Frontal larger avicularian mandible with two 

 retractor muscles and an avicularian gland. 



x 200. 



e. Oral avicularian mandib'.e with retractor 

 muscles and an avicularian gland, x 200. 



