XU INTRODUCTION'. 



(p. 81), Latlriis tatei (p. 147), Leucozonia staminea (p. 151), 

 Pseudovaricia mirabilis (p. 160), and Murex otwayensis (p. 177). 



Althougli Tve occasionally find that the main features of the 

 sculpture of the adult are foreshadowed even in the protoconch, 

 that is by no means a general rule. The protoconch of Pleurotonia 

 alta (p. 45), for instance, is perfectly smooth, yet in the brephic 

 stage a most pronounced peripheral carina makes its appearance ; 

 on the other hand, in P. wanganuiensis (p. 46) the strong spiral 

 ornament obtains from the protoconch to the ephebic stage, though 

 profuse additional ornament was suddenly produced in the brephic 

 stage. On this evidence, and seeing how closely allied the two 

 species are in some other respects, one would assume that the latter 

 species most probably descended from an earlier stock of the former. 



By way of contrast we find in Bathytoma angustifrons (p. 49) 

 and Morio gradatu (p. 201) that but few of the main features of the 

 ornament in the adult were foreshadowed even in the brephic stage, 

 and that ornament is not of a permanent character, but was modified 

 at the caprice of the individual. That, and similar evidence given 

 in this Catalogue, points pretty conclusively to a general rule that 

 may be established (at least, so far as these Australasian fossils are 

 concerned, and it is possibly of much wider application), namely : 

 that when the main features of the ornament are foreshadowed 

 in the early brephic stage, and especially when they obtain even 

 in the protoconch, that ornament may be regarded as of value 

 in the determination of species ; but when, on the contrary, the 

 ornament does not make its appearance until the late neanic stage, 

 and is not, even in an elementary sense, completed until what may 

 be regarded, by analogy, as the early ephebic, that ornament merely 

 characterizes the individual, and is only of negative use for the 

 purposes of classification. 



The size of the protoconch is very variable (e.g. Cancellaria 

 wannonensis, p. 66), as is well known, even in the offspring 

 of a single individual ; that difference being commonly attributed 

 to carnivorous proclivities on the part of the larger specimens when 

 in the embryonic stage. In this connection it is noteworthy that 

 the size of the protoconch does not seem to have much influence 

 in determining the size of the shell in the adult. The larger 

 protoconch is not ver}' frequently, it would seem, accompanied 

 by the production of a larger adult shell than comes from a much 

 smaller protoconch, that is, in the same species. There are, 



