200 



K. MITSÜKUEI : STUDIES ON 



convinced me that, for tlie present at least, the two genera should 

 be kept apart. When a dorsal arabnlacrum is looked at from the 

 inside, there is in Lœtmogone only one series of ambulacral 

 vesicles on the outer side of the said ambulacrum ; while in 

 Ilyodcemon there arc two series of these vesicles, one on both the 

 outer and the inner sides of the ambulacrum. 



46. Ilt/odœnion ijhnal Mitsukuiu. 

 (PI. YI., fig. 55 ; textfig. .37). 

 Ihjodœmon yimai Mitsukukt 1897/>, pp. 133 — 5. 

 Specimens examined : — 



