A REPORT ON* 



THE CYCLOSTOMATOUS BRYOZOA OF JAPAN'. 



343 



9. Crisulitiora Ijimai n. sp. 



Zoarium bushy, attached to substratum by inferior end of basal inter- 

 node, without rootlets ; internodes and branches decumbent, being bent 

 dorsally in a bow-like manner ; both these milky white, articulating with 

 one another by corneous joints of an yellowish or a bluish yellow colour, 

 opaque at truncate free end of branches, gradually narrowing towards base, 

 minutely punctate all over ; dorsal surface somewhat flattened, transversely 

 wrinkled ; ventral surface rounded, with zooecia standing out in two lateral, 

 longitudinally running zooecial zones separated by a narrow median space. 

 Internodes 9-17 mm. long, the longer ones bearing branches which spring 

 out usually solitarily, rarely two or three together at a time and that at an 

 indefinite height of the internode. Zooecia arranged in numerous succes- 

 sive series in each zooecial zone, those of the two lateral zones alternating- 

 with one another. In the distal parts of an internode, each zooecial series 

 consists usually of four, and sometimes of three, zooecia. Proximally the 

 number decreases, so that in the lowest parts each series is made up 

 of three or two zooecia. Zooecial aperture circular or sub-elliptical, 

 0.12 x 0.14— 0.2 x 0.16 mm. large, always less wide than greatest width of 

 zooecium, slightly thickened at margin ; most apertures provided with the 

 so-called " closure " occurring a short distance within them, its surface 

 sparsely pored. Branches without basis rami ; each branch arising from an 

 enlarged special zooecium. This is, in the case of solitary branches, in- 

 variably the innermost zooecium of a series. When a second branch occurs 

 on the same internode, it is borne likewise by the innermost zooecium 

 belonging to another series of either the same or the opposite zone and 

 either directly adjacent to the series bearing the first branch or separated 

 from this by a few intervening series. The third branch is borne on the 

 zooecium next outer to that which bears the first or the second branch. 

 The third and fourth zooecia of a series, counting from the inner end never 

 carry a branch. A single ovicell was met with in the specimen. It is an 

 inflation of the midventral parts between the zooecial zones, extending from 



