108 ON THE LITTORAL FAUNA OF N. E. ATJSTRALIA, 



cliffs and "boulders along the shore. A few serpulse and a number 

 of a small species of Balanus may be noticed, but no molluscs and 

 no seaweeds. The broad green fronds of the Ulva latissima so 

 frequently covering the rocks in temperate latitudes, are absent 

 as well as the confervoid growth of the sides of the rocky pools. 

 The comparative absence of Algae and Confervse prevails every- 

 where as much around the coral reefs as on the rocky shores, but 

 in the latter places, the mollusca vary in amount. Along the 

 black rocky boulders of Island Point, Port Douglas, molluscan 

 life is very abundant. A very large portion of the rocks is 

 literally covered with a species of oyster. In habit and in mode 

 of aggregation it is closely similar to the Port Jackson oyster, 

 Ostrea mordax, Gould, but it is a different and probably described 

 species. The edges of the valve are much more regularly undulate 

 so as to have a frilled appearance, and the lower or adherent 

 valve is subquadrate, and the edge comes up squarely all round 

 just like a little box into which the upper, free valve fits like a 

 lid. I believe it to be Ostrea cucullata, of Born (J/?<s. p. 114, plate 

 6, figs. 11 and 12) and Chemnitz Ostrea cornuco^icB (Conch. Cab. 

 8, p. 41, plate 74, f. 679). Born describes it as '' SheU oblong, 

 parasitical, with longitudinal plaits and strong imbricated, trans- 

 verse wrinkles ; upper valve flat, and its margin by the hinge 

 somewhat toothed." In the figure of Born the lower valve is 

 concave and ends in a long beak. This is a common form but not 

 the usual one. It is quoted by various authors as from the 

 Atlantic (West coast of Africa), Ascension Island, China, Arabia, 

 and Sumatra. Humphreys (Conchology, or Natural History of 

 Shells) says it is found in the South seas. I observed the same 

 species in many places on blocks of dead coral on the reefs, 

 in fact it seems to be abundant everywhere upon the coast within 

 the tropics. It is of delicate flavour, and highly prized by the 

 inhabitants, both black and white. 



Next to this in abundance upon the rocks is Flaraxis sulcata, 

 called perrywinkle by the settlers, and is boiled and eaten in 



