92 NOTES ON AUSTRALASIAN SHIPWORMS, 



the whole of its existence in perfectly fresh water in the Hurree- 

 gonga, an anabranch of the Ganges River, India ; and which 

 indeed is unknown elsewhere. Kirk noticed an undetermined 

 species a hundred miles from the sea in the Zambesi River, S. 

 Africa.* 



A difficulty which at once confronted me in describing the 

 novelty was to select the genus most appropriate for its reception. 

 The accepted classification is based on the form of the palettes. 

 Continued observation and reflection have persuaded me that 

 these features are not deserving of that classificatory value at 

 which Grould and Wright have estimated them. Their structure 

 and position must expose them, before any other portion of the 

 animal, to stress of modification in change of environment. The 

 soft parts of the anterior trunk should be preferred to the hard 

 in the choice of features to guide the systematist. An examination 

 of published figures and of a considerable series of Australasian 

 specimens shows me that the siphons of the Terediclce are variously 

 divided or united, and vary also in being surrounded or not by a 

 cup-like outgrowth of the mantle. These are the features on 

 which I rely for a clue to the natural division of the family. 



The species under consideration cannot be included in the 

 genus Teredo of Linne, for the type of that, according to the 

 figures of Forbes and Hanleyf and other writers, entirely lacks 

 the cup-shaped mantle which here surrounds the bases of siphons 

 and palettes. 



Uperotus, Guettard, judging from the engraving of Griffiths,; 

 differs by the siphons being united to the tips. 



The animal of Kuphus, Guettard, is still unknown, but as 

 Wright points out we may safely deduce from the shelly tube 

 that the animal has the siphons separated for most of their length. 



Nausiloria, Wi'ight,§ however, conforms to the pattern under 

 study, and in this respect does not difier from the previously 



* Jeffreys, British Conchology, iii. 1865, p. 147. 



t British Mollusca, 1848, PI. F. fig. 1. 



X Cuvier's Animal Kingdom, 1834, xii. Mollusca, PI. xviii. f. 3a. 



§ Op. cit. xxiv. p. 452. 



