262 EXPLANATION OF PLATES. 



a., ala (rudimentary wings); s.p. 1 «. 6., strongly developed 

 spines on posterior edge of dorsal plate, 1st abdominal seg- 

 ment ; s.p. X , three stout spines a little behind the latter ;/. , 

 femur ; t., tibia ; trs., tarsus, divided into five joints. 

 Fig. 3.— Bones of left fore-limb of a clinging mammal, the two-toed 

 sloth (much reduced). 



^j 4. — Second limb, left side, of a species of Phalangium (" Har- 

 vestman ") to show reticulation of tibia (t.), as in Nyderibia, 

 and " vegetative repetition " of tarsal segments, x 10. 



,, 5. — Fore limb, left side, of flea {Pulex hominis), in further 

 illustration of curved clinging claws. 



,, 6. — Rudimentary ala of Nyderibia, with spines. 



,, 7. — Two of the dorsal spines of 1st abdominal segment, one in 

 outline only, the other showing fluting, x 75. 



,, 7a. — Diagrammatic section of spine. (The structure of these 

 spines recalls that of the teeth in the Labyrinthodonts. ) 



,, 8. — Right prothoracic spiracle, x 50 

 ,, 9. — First abdominal spiracle, x 50 



,, 10.— Rough sketch of head of Flying Fox. Drawn by Dr. Rowe. 

 ,, 11. — Sketch of Skull of Rousette. Drawn by Dr. Be van Lewis. 



All the others drawn by Tuflen West. 



Plate XXIV. 



Fig. 1. — Specimen of Batrachospermum moniliforme, natural size. 



,, 2. — Piece, x 20, to show general appearance. 



,, 3. — Portion, x 150, to show details : — st.f., stem-fibres ; r.f., 

 root-fibres, supposed by Berkeley to be analogous in fujiction 

 to the stomata of higher plants. The difterence may be 

 expressed as corresponding to that between external gills and 

 internal lungs ; br.f. , branch-fibres, curiously like the myce- 

 lium of fungi ; sp. , spore. 



Lower portion of same plate. 



Hairs on Upper or Anterior, and Lower or Posterior Surfaces 

 of Frond of Elk's Horn Fern :— 



,, 4. — The upper surface, x 50. 



,, 5. — The lower surface, x 50. 



Drawn by Tuflen West. 



