224 



PRELIMINARY OBSERVATIONS ON A NATURAL HISTORY 



large fish, weighing several hundred weight, apparently an 

 Oliuorus, that was occasionally taken in nets at the mouths of 

 neighbouring creeks I was unable to ascertain whether the 

 species was identical with OHgoru* Mitchell 'i Cast, of the West 

 Australian sea-board, or represented one of the two Queensland 

 types, terra-regina and 0. goliath, L)e V. It is possibly distinct 

 from either of these. A species of so called Barramundi — 

 probably the Giant Perch, I, ites calcarifer, Bl. — was reported to 

 me from the rivers and lagoons inland, from both Cambridge Gulf 

 and Tort Darwin. Specimens could not be obtained at the 

 time for identification. 



In connection with the Invertebrate animals collected the 

 class of the Mullusca claims the first attention. In this section 

 I have obtained the able assistance of Mr. C. Hedley of the 

 Queensland Museum, who has undertaken the identification of 

 the majority of the shells collected and has supplied the accom- 

 panying list. There are not so far as I am aware many novelties 

 among these Mollusca, though a certain portion of them may 

 possibly prove of value in illustration of the local distribution of 

 of previously known species. One of the forms, however, 

 obtained at Cambridge Gulf, is of more than ordinary interest, 

 and is apparently new to science. This is an exceedingly minute 

 species of oyster I found growing in great abundance, not only 

 on the stems, roots, respiratory shafts, Or so called " cobbler's pegs " 

 of the White Mangrove, Aricennia officinalis, but also, as shown in 

 the examples here exhibited, so thickly encrusting the growing 

 leaves of the same plant, that as many as fifty specimens may be 

 counted on one leaf. The longest measurement of the finest 

 examples does not exceed one quarter, or three eighths of an inch, 

 while in the majority of Instances it is considerably less. '1 hat 

 the form is in its adult condition, and does not represent the 

 undeveloped stage of some larger species, was demonstrated by 

 the circumstance that numerous examples dissected and examined 

 witli the microscope were found to be full of well developed 

 embryos. The habit of the species is moreover essentially 



