THE NAUTILUS. 123 



■was a young Gundlachia ! In his list of Tasmanian mollusca, 1890, 

 he simply drops his A. woodsi without mentioning that it is a 

 young Gundlachia. I have not yet found full-grown specimens of 

 our Gundlachia, but I hope to succeed later on, and it is to be ex- 

 pected to be a similar form to G. peiterdi Johnston. 



Prof. Hutton suggested to me that this Gundlachia might, per- 

 haps, have been introduced from Tasmania on aquatic plants, which 

 were used in packing trout ova, and as our fish-hatching ponds are 

 in communication with the river Avon, there is all possibility of 

 this being really the case. However, there is one objection. Up to 

 the present day I found our G andlachia only on aquatic plants in 

 the lower parts of the river, from the outflow of Horseshoe Lake to 

 New Brighton, but not upward between this outflow and the fish- 

 hatchiug ponds. This makes it very likely that Gundlachia occurs 

 in the swampy Horseshoe Lake, difficult of access, and was washed 

 down in the river Avon when the canal was cleared from Anacharis 

 weeds. If this mollusk is really indigenous, it will, no doubt, be 

 found in localities where the introduction from Tasmania is out of 

 question, but as long as this is not the case, we must remain doubt- 

 ful on this point. 



In the "Reference List" I published vvith my friend Mr. Ch. 

 Hedley, of Sydney (Proc. Linn. Soc. N. S. W., vol". VII (2) p. 624), 

 he put down Ancylus tasmanicus Tenison- Woods, as being synonymous 

 with A. ivoodsi. This is wrong, as the former is quite different, and 

 I believe it to be really an Ancrjlus. A. audralicus Tate and A. 

 smithi Cox are very likely also young forms of Gundlachia. A. 

 asslmilis Pett. and A. oblonga Pett. I have not seen. It would be of 

 highest interest to examine the dentition of the Caledonian A. reti- 

 culatus Gassies and A. noumeensis Crosse, which Mr. Hedley thinks 

 to be nearly allied to the so-called A. woodsi. 



2. Rkytida meesoni Suter (Reference List, 1. c. page 631) is no 

 Rhytida, but a Paryphanta, as the animal lays calcareous eggs, 

 whilst the genus Rhytida is considered to be viviparous. The genera 

 Paryphanta and Rhytida are in the shells, the exterior of the ani- 

 mals and the radula so nearly allied, that it is not always easy to 

 separate them. Very likely the genital organs will show generic 

 differences, and it is my intention to study the anatomy of these 

 genera as soon as opportunity offers and time permits. 



3. Thalassohelix ziczuc Gould. There was always some doubt 

 whether this shell was really a New Zealand species or not, and at 



