IIIROSIII OHSHIMA : 



anterior notches and tentacular canals are equally applicable for some 

 other species, as f. i. Pseudocucumis acicula [LUDWIG 20» Taf. VI., 

 F'g« 17], Phyllophorus cebiiensis [ThÉEL 46, Pl. IX., fig. 4; LUDWIG 

 26, Taf. VI., Fig. 10], Ph. frauenfeldi LUDWIG [20, Taf. VI., Fig. 

 22], Ph, holothurioides [LUDWIG 20, Fig. 23], and Ph. celer KOEHLEK 

 et VANEY [17, Pl. I., fig. 24]. Judging from SlUITER's figure of the 

 calcareous ring of his Orcula purpureo-punctata [44, Taf. VI., Fig. 

 15], which clearly shows the presence of three notches in each radial 

 segment, it seems highly probable that in that form there exist 

 twenty tentacles, of which five were probably overlooked on account 

 of their very small size. Also LUDWlG's statement [25, P- 814] that 

 the anterior part of the calcareous ring of his Phyllophorus brocki is 

 exactly similar in form to that in Orcula tenera, leaves room for 

 suspecting if he has not overlooked a small notch at top of the 

 narrower process of radial segment. 



Here it may be stated that in the Molpadiidœ the fifteen 

 tentacles present are usually given off in the same manner as in 

 Orcula. Ludwig [28, p. 590] has stated in his work on Ankyroderma 

 musculus (Risso) that the branching of tentacular canals stands in 

 intimate relation to the form of calcareous ring. Each radial canal 

 should give off three tentacular canals in an alternate manner, and in 

 paired radii the first and the third are always dorsally directed. The 

 midventral radial canal should usually send out the first and the 

 third tentacular canal to the right, but occasionally to the left. 

 GeroULD [14, pp. 161 — 162] came to the same conclusion from his 

 examination of Caudina arenata (Gould). LUDWIG [26, PP- 87 — 88] 

 and ÖSTERGREN [36, p. 4 and 37, P- 2o8] took the above branching 

 mode as valid in all the forms of the family. Clark [8, P- 137] has 

 stated that " there are not three (tentacles) in each interradius, as 

 might be supposed, but four in the middorsal interradius, three in 

 each of the latero-dorsal interradii, three in one of the ventral 

 interradii, and two in the other." 



