28 H. H. GRAN AND K. YENDO. M.-N. Kl. 



The most remarkable character of the plant here treated is that the 

 spines connecting the cells in the chains have no sort of joint throughout 

 their whole length. As far as our researches extend, the spines of SfepJiano- 

 jiyxis, hitherto described, meet each other midway. Only one form, 

 illustrated in Schmidt's Atlas Diatom. Taf. 130, fig. 29 and 31 as y>Ste- 

 2)]i((n()i)yxh sp. novY«, has long spines extending from one frustule to 

 the other. But in his drawing the apices of the spines are decidedly 

 pointed and free, not spanning between the two frustules as in our species. 



The meshes are regularly disposed in the typical form, parallel to 

 the longitudinal axis of the frustule, but often in oblique rows. In some 

 specimens from Otaru Bay, there were many frustules in which the 

 primary and secondary valves had different sorts of meshes. In the 

 primary valves two or three meshes near the girdle were often confluent 

 to form labyrinthoid lines, while in the others no such irregularity could 

 be seen (fig. 16 b). In any case the size of the meshes in an individual 

 is nearly constant, amounting to 4 — 5^/0 in 10 /<. 



The diameter of the frustules varies from 27 to 38 u, and the valves 

 are hemispherical at the top. Just before division, the height of the cell 

 may attain 90 /<. 



The spines are 8 — 12 in number in an irregular circle round the 

 top of a valve. 



Loc. Otaru Bay; Volcano Bay (Yexdo). 



