1898.J APPENDAGES IN THE AETHEOPOUA. 941 



uncertain. But some degree o£ eii'cumstantial evidence that the 

 reproduced flageUum has the normal number is afforded by 

 observations (18, 68) that it is very often of equal length with its 

 fellow at the first ecdysis after mutilation. 



But that the reproduced appendages of Crustaceans are not 

 invariably replicas of the normal is shown by the experiments of 

 Przibram (67) and by the remarkable cases described by Herbst (48), 

 Hofer (50), and Milne-Edwards (60) of various Decapods replacing 

 an eye by an antenna-like structure. These instances, however, do 

 not fall under (b) above, and for the present must stand apart as 

 isolated cases with special features. Borradaile (11) has recently 

 described certain instances of abnormal antennce in Maerura- 

 Anomala which may possibly have arisen in connection with repro- 

 duction, but these also differ from the cases to be described under 

 (b) in the possession of more than the normal number of joints. 



Isopoda. — Heineken (47) made a few observations on the 

 reproduction of the antennce of a Madeiran Armadillo ; bub his 

 account unfortunately gives no details beyond stating that the new 

 grovrths were sometimes " perfect " and sometimes " rudimentary." 



Cirripedia. — Darwin (22) speaks of the regeneration after injury 

 of the cirri (thoracic limbs) in Balanus as though the new structures 

 were like the normal. 



AEACHNinA. Araneidce. — The pedipalps, walMng-legs, and 

 spinnerets appear, when reproduced, to be invariably like the 

 normal in all respects except size. Blackwall, however, mentions 

 that if the pedipalp of a male Spider is mutilated between the 

 penultimate and final ecdyses, the spei'm-case of the digital 

 (terminal) joint is not developed on the attainment of maturity. 

 This structui-e, which is distinctive of the adult condition, is 

 produced in cases where mutilation is performed two ecdyses before 

 maturity. 



Mteiapoda. — Newport's observations (61) indicate that the 

 lualking-legs, when regenerated, though of small siz^, are of normal 

 structure. 



Insecta. Orihoptera-Saltatoria. — It appears, from the recent 

 investigations of Griffini (loc. cit.), that in this group reproduced legs 

 possess the normal number of joints throughout. 



Keuroptera. — Watson (77) found that injury to the leg of an 

 Agrion larva resulted in the production of a limb of normal 

 aspect at the next ecd^'sis, except that the clawof the terminal tarsal 

 joint was absent. 



UnDEE (b) MAT BE PLACED THE FOLLOWING OBSEEVATIONS : 



Aeaohnida. Scor'pionidce. — The cases of regeneration referred 

 to above as shov\n to me by Mr. E.. I. Pocock were a Buthus and 

 a Scorpio, both immature. In the former the leg had been broken 

 very near the base of the femur, and from this point there grew 

 out a dwarf tarsus with terminal claws of normal appearance. In 

 the lattej- case a break had occurred in the patella, and borne 

 apparently directly on the seat of injury were a set of small but 



