140 IWA.TI IKEDA. 



only case in whicli this multiplicity of the ventral hooks has 

 been recorded in the Echiuroids, the hooks are comparatively 

 small (about O'l mm. in height), and are crowded together, 

 without showing any regular arrangement, at a spot nearly in 

 the middle of the genital groove (fig. 6). They are almost 

 transparent, light brown in colour, and have a slightly curved 

 sharp apex. Another point of peculiarity is shown by the 

 fact that the hooks, when examined from the inside of the 

 skin, are not borne on the usual muscular cushion provided 

 Avith radiating muscles, as in the case with all known Echiu- 

 roids. They are simply rooted in the thickness of the 

 epidermis, not even a slight bulge of skin being present. It 

 was the discovery of these hooks that made me feel the neces- 

 sity of a re-examination of the type specimen of Hamingia 

 ijimai, which has many points of tigreement with the present 

 species. As I remarked in the introductory paragraphs, Mr. 

 Takahashi examined the type specimen for me and found out 

 ten small hooks in the middle of the genital groove. Fig. 7 

 is a sketch of the hooks of Haming-ia ijimai drawn by Mr. 

 Takahashi. Here we see the ten hooks directed posteriorly 

 and crowded irregularly. Judging from this figure, which 

 was drawn by means of Abbe's Zeichenapparat, it will be 

 seen that these hooks of Hamingia ijimai are straighter 

 and larger than those of the present species. As these hooks 

 in both species are minute and embedded in the narrow 

 streak-like groove, I unfortunately overlooked them when I 

 was examining the type specimen of Hamingia ijimai. 



Referring to the internal anatomy, the animal shows some 

 noteworthy characteristics. 



As some loops of the alimentary canal were, as before 

 stated, severed off, the real state of connection of these torn 

 loops with others still remaining in the natural position, and 

 further, the actual and relative lengths of the three tracts 

 (fore-, mid-, and hind-guts) of the whole canal, could not be 

 made out. As far as the general characters of the canal are 



(Bonelliu miyajiinui. Thalasseiua tienioides, and T. elegaus)," 

 ' Joiu-u. Coll. Sci. Imp. Univ., Tokyo. Japan," vol. xxi, art. 8, 1W)7. 



