(2 S. HIROTA. 



(Fig. 11) and to make that arm less rigid at that point. The vertebral ridge 

 is also somewhat deranged here. Huch a condition of things may appear 

 at the first sight as an indication of the breaking-off of the arm. ]>y com- 

 parisons of various forms we k'now, however, that such a state is attainable 

 in later stages of the regeneration of an arm and that there are intermediate 

 stages linking such and an early stages of regeneration. In early stages 

 we observe on tbe external surface a distinct junction l)etween the old, 

 and the new parts, as the latter distinguishes itself by its shape and small 

 size of its ossicles. The new part is also characterised interiorly ])y a weak 

 development and sudden ending of the vertebral ridge as well as of the radial 

 coeca, accompanied by the corresponding development of the ampullae and 

 the hepatic sacs. But all these tokens become gi-adually obscure throngh an 

 incessant growth of various organs, and at length the new part becomes 

 indiscernil)le from the old part, or sometimes a slight disturbance of the 

 structure, as stated above, is left for a long time at the junction. Haeckel''^' 

 seems to think that, in L. diplax and L. ornithnpi/s, those elongated arms, 

 having a ' Fissinsstrictur ' at the distance from the disc are in preparing to 

 break themselves. He figured some examples,* but he gave no criteria of 

 differences ])etween the arms to be cut off and the arms have been regenerat- 

 ed, so that his interpretation may be doubted. In short, I am inclined to 

 consider the local constriction of arms as a remnant of the junction, not as 

 the preparation of the act of self-breaking, at least in LhicJcia multifora. 



I find in m}^ collection three speciemens, in each of which an arm has 

 been very recently dropped — the first at 2.5 cm. the second at 2.2 cm. and 

 the third at 1.1 cm: from the disc respectively — and the wounds are not yet 

 healed, but the body cavit}- witli the internal soft organs are directly exposed. 

 In these and many others having one or more old wounds covered by a 

 membrane, we notice that the wall of a wound is usually irregular in shape, 

 even twisted or plaited as if the arm was broken through a violent stress. 

 From these facts we learn that at least in these examples the arms were 

 comparatively suddenly cut off, without a long course of preparation. 



* One of the exninples is copied in Tiano-'i? (A.) 'T/oliTlinoh der vprp^leichenden An.itouiie. 

 Xeunte Anflao-e. 18SS.' 



