Carpknticr — The Apteryfiota of the Seychelles. 49 



it. coetivy. 



Thysanura. 



Acrotcha coUaris. 



III. A^riRANTE AXD FaRQUHAR GROUPS. 



Thysanura. 



Isolepisvia bisefosa. Eagle Isl. (Amirante), Cerf and Providence Jsls. 

 Farqnhar. 



IV. Aldabra. 



Thysanura. 

 Isolepisma hisetosa. Acrotelsa elongaia. 



Acrotelsa collaris. A. Scotti. 



COLLEMBOLA. 



Axelsonia thalasso2}hila. 



The poverty of tlie exclusively coral groups (Coetivy, Amirante, Farqnhar, 

 and Aldabra) in Apterygota is evident from the above lists (II, III, and lY), 

 and is highly suggestive when compared with the fairly rich fauna of the 

 granite islands of the Seychelles archipelago proper (I). The only Collembolan 

 found outside these granite islands is Axelsonia thalassophila, from the coral 

 Aldabra group — a reef-haunting insect already known from the east coast of 

 Madagascar. This spring- tail may be regarded as at least a possible subject 

 for "accidental" dispersal across sea-channels. According to Gardiner's 

 conclusions, the present Aldabra group could never have formed part of any 

 continental tract, and the transport of small insects by sea-birds is not to be 

 dismissed as impossible. Still the presence of delicate shore-haunting animals 

 on separated islets or analogous stations is strongly indicative of former 

 continuity, or at least approximate continuity ; and though Aldabra may be 

 " oceanic," the ancient existence of continental islands in the vicinity is 

 certain. The presence of Axelsonia in Japan is noteworthy in this connexion, 

 pointing to a former very extensive range of the genus. 



The Isolepisma and the Acrotelsae found in the Amirante and Aldabra 

 groups may have been introduced by means of human intercourse or 

 commerce, as some at least of these species frequent the neighbourhood of 

 dwellings, or live iudoors. The contrast -afforded to the scanty representation 

 of the Apterygota on these coral islands by the comparatively rich fauna of 

 Mahe and Silhouette, from one or both of which come all the Machilidae, 

 lapygidae, Campodeidae and (except for Axelsonia) all the Collembola of the 

 R I A. r.;oc., VOL. xxxin., skot, b. \H'\ 



