1898.] APPENDAGES m TitE ABTHEOPODAi &27 



those of Eeaumur himself on the legs of Palinurus and those 

 quoted by him as having been performed on Crabs at Gruadaloupe by 

 Le Pere de Tertres. Keaumur (69, 70) noted that the autotomous 

 rupture always occurred at the groove marking the fusion of the 

 ischiopodite to the basipodite. [The meaning of this peculiar fusion 

 between two leg-joints in Crustaceans and many Tracheates has 

 recently been discussed by Bordage (9).] Reaumur's observation 

 has been often confirmed for all Decapods which exhibit autotomj\ 

 Sixty years later the subject was studied by Bodier (4), while 

 during the present century further observations on Decapods have 

 been made by MacCuUoch (56), Heineken (46, 47), Couch (21), 

 Goodsir (38), Spence Bate (1), Chantran (18), Putnam (68), 

 Howes (51), and Brook (17). Milne-Edwards (59) and Huxley 

 (52) have discussed the phenomena described ^ During the Last 

 few years more extended experiments on autotomy in particular 

 have been made by Predericq (loc. cit.), De Varigny (74), and 

 Parize (63). It seems certain that the act is reflex in nature ; but 

 on other points there is much disagreement amongauthors, especially 

 whether it is necessary for the limb to come into sharp contact 

 with the carapace. In Astacus a few experiments by myself tend 

 to show that the comparatively feeble autotomy of this genus 

 is exhibited only when the carapace is employed as a point d'ajJimi. 

 But in this, as in other Decapods, the results of experiments on 

 autotomy are much influenced by the age and general condition of 

 the animal and by the mode of stimulation employed. There is, 

 however, no doubt that most Decapods have a certain region of 

 the limb specialized for autotomous loss, and with this condition 

 has arisen the localization of regeneration. Pouchet (66) and 

 others have pointed out that the loss of a limb at the suture 

 entails comparatively very slight bleeding. It has often been 

 noticed that injury to more distal portions not followed by 

 autotomy results in the eventual loss of all parts up to the suture, 

 though in Astacus I have seen distal joints retained two months 

 after mutilation. Groodsir (38) has given a description of a special 

 structure in the basipodite of Carcinus, which he regarded as an 

 organ for producing new limbs. The account, however, seems to 

 require confirmation. But whether the regenerative power is 

 localized as above in those Decapods which do not appear to perform 

 autotomy, such as Crangon, Falcemon, and the young of Fagurus 

 (74), is at present uncertain. Moreover, it is doubtful whether the 

 flagellum (endopodite) of the antenna of Decapods exhibits true 

 autotomy, and whether regeneration is confined to the protopodite, 

 or may commence more distally. In Homarus Brook (17) has 

 mentioned a " throwing off " of the flagellum, and its complete 

 regeneration has been observed by several authoi-s. 



Aeachnida. Araneidce. — Experiments on autotomy and regene- 

 ration were made on Spiders by Heineken (46, 47), who found that 

 reflex casting of the walking-legs occurred invariably at the suture 

 marking the fusion of femur and coxa. He considered that a 



' See also Morgan, Zool. Bulletin, May 1898. 



