220 
HORN EXPEDITION—MOLLUSCA. 
A P P E N D 1 X. 
NOTE.S ON ANATOMICAL CHARACTERS. 
By C. HEDLEY, Assistant in Zoology to the Australian Museum, Sydney. 
As Professor Tate has already stated, the specimens upon which he relied for 
the examination of soft parts unfortunately perislied before he was able to investi¬ 
gate them. These notes are therefore based on few species, and are necessarily 
meagre. The material studied consisted of snails killed for the most part 
in spirits and collected and forwarded by Professor Spencer. These were 
specifically determined from shells named and sent by Professor Tate to the 
Australian Museum. Some interesting results were however yielded by an 
examination of this small collection. Viewing the fields of anatomy and phytogeny 
from the standpoint to which Pilsbry’s “ Guide to tlie Study of Helices ” has lately 
advanced science, the facts, hereinafter detailed, show that between some Australian 
snails, whose dentition and shells are much alike, a line of cleavage is indicated by 
the reproductive system ; while the same feature knits together species hitherto 
sundered by the systematist. From its neighbours the genus Xanthonielon is 
distinguishable by the sliortness of the spermatheca stalk, and by a peculiar form 
of the male organ here interpreted as an invagination of the epiphallus. It is 
submitted that these characters entitle Xanthonielon to full generic recognition. 
Anotlier result of these inquiries is a more correct classification of the genus 
Microphyiira, hitherto considered a member of the carnivorous group Rhytididie. 
Fi’om this it is disassociated by a jaw and radula which I was able, but indistinctly, 
to view. Sketches of these now presented will, to my inalacological readers, 
suggest Laonia and Flanunulina as the next of kin. 
Bithinia australis, Tryon. 
tSome specimens dried in mud for more than a year 
revived promptly on being placed in water. From one of 
these I sketched the figures of animal, operculum (Fig. A) 
