6-8 



YAICHIRÔ OKADA: 



position as the above, with nearly semicircular mandible directed 

 obliquely downwards and showing weakly reflexed and serrated distal 

 margin. Form c (/) is of a nearly oblong outline, with triangular 

 mandible hooked and weakly reflexed at apex ; occurring in the 

 posterior parts of zooecial surface, together with either of the two 

 preceding forms. Vicarious avicularia {g) larger than any frontal 

 avicularia, provided with large shield-like mandible pointed and slight- 

 ly curved at apex. Dorsal surface convex, nodulous, divided by 

 vibices into numerous regularly shaped areas, each of which exhibits 

 two avicularia. One of these agrees in shape and size with the first 

 kind, and the other with the second kind, of the ventral avicularia. 

 Ooecia small, orbicular, weakly inflated, with a plain narrow fissure in 

 the middle of its smooth surface; the lower margin is prolonged into 

 a lamina and extends, some way into the zooecial aperture. 



This is another species of the Retepo7'ella group. It is represented 

 in the collection by a small and a moderately large colony, and by 

 fragments. They were obtained at Onigasé (117-234 fms.), at Yodomi 

 (64-78 fms.), and at a spot off Jôgashima (80 fms.). The species 

 somewhat resembles Reteporella minor Ortmann, but differs from it in 

 the absence of oral avicularia and in the presence of the large oblong 

 ventral avicularia. 



Adeonidae. 



Adeonella Busk 1884. 



I . Adeonella japonica Ortmann. 

 Pl. VIII., fig. 9 ; textfig. 6. 



Adeonella japonica Ortmann 1890, p. 54, pl. IV, fig. II. 



The zooecial features vary considerably according to age of the 

 animal. Young zooecia (textfig. 6 ò.) are of an elongate oval form, 

 with raised central parts surrounded by a weak elliptical ridge and 



