TOPOGRAPHICAL, ECOLOGICAL, AND TAXONOMIC NOTES. 291 



their coats are usually of a corky, or woody texture, and 

 they have one or more watertight compartments, which 

 serve the purpose of floats, and act as a protective agency 

 against the intrusion of the saline water. A by no means 

 insignificant factor in the moulding of the fruit, is the 

 danger of being dashed to pieces by the waves upon a rocky 

 headland, or ground to powder on a shingle beach, while 

 en voyage. The most suitable contrivance to neutralise 

 the effects of such an occurrence, is the production of 

 strengthening ribs, which are frequently extended into 

 wing-like appendages, or, in the Spinifex, an elongated 

 spine (awn) proceeding from the apex of the fruit, which 

 act as collision buffers. 



[In the scientific portion of his Presidential Address to 

 the Royal Society, "An Ecological Sketch of the Sydney 

 Beaches," 1 Mr. Oharles Hedley cites a series of devices 

 adopted by certain molluscs, characteristic of the rocky 

 surf-swept headland, in the construction of their dwellings, 

 t>y which the sculpture of the shell is so contrived as to 

 produce extensions or projections, calculated to strengthen 

 its resistance to wave action, and figures (p. 57, fig. 19) 

 such a shell, armoured with massive rings.] 



The material of which the fruit coat is composed, corky, 

 pithy, felted, membranous, etc., is of a tough but yielding 

 character, not easily fractured. The members of the strand 

 community are as a rule prolific seed bearers. Two grasses, 

 Spinifex hirsutus Labill., the "Spiny Rolling-grass," and 

 the littoral "Fescue," Festuca littoralis Labill., play an 

 important part in the building and upkeep of the frontal 

 dune embankment rising immediately behind the strand, 

 the former, in the area inspected, representing approxi- 

 mately 50% of the herbage clothing its slopes. 



1 This Journal, xlix, (1915). 



