14 ART. 7. — K. KINOSHITA : ON SOME MURICEID CORALS 



According to Wright and Studer, Acis nutans Ducii. & Mich. 

 does not belong to this genus, but should be a form very closely 

 allied to Keroeides koreni Wr. & St. Acis solitaria Pourtales 

 seems not to have been taken into consideration by them, or by 

 Kidley either. At any rate, this species is very imperfectly 

 known. 



In Acis ijimai and m/iyajimai, the scales on the calyx, into 

 which the anthocodia is nearly completely retractile, are very 

 often arranged in such a way that the four scales alternate in 

 successive heights, while in many other cases a certain irregular- 

 ity predominates (PI. II., figs. 13, 17 and 18). Judging from 

 the figure given by Duchassaing and Michelotti, Acis gauda- 

 lupensis seems to exhibit a similar arrangement of the calyx- 

 scales. In another species, which I have identified with Acis 

 pusiulata Wr. & St., I could often perceive a regular but some- 

 what different arrangement of the calyx-scales. In this case 

 they were set opposite to the tentacles at the margin of the calyx 

 and alternately in the lower ring. This mode of arrangement, 

 eight scales in one ring, seems to be due to the weak development 

 of the scales and seems to represent a more primitive condition 

 than that observed in the cases of the two former species. 



In Acis ijimai and miyajimai, the operculum is composed 

 of two large, almost longitudinally set, spicules and of two rows 

 of somewhat smaller spicules arranged at the base of the former. 

 But in Acis jnistulata, a single series of some relatively large 

 spindles is set transversely at the base of the large opercular 

 spicules and in touch with those of adjacent radii. The modes 

 of arrangement of anthocodia spicules referred to above differ so 

 much that the homology of the longitudinal spicules in the two 

 cases is made doubtful. 



