384 PROCEEDINGS OF TflE MALACOLOGICAL SOCIETY. 



and both were received from Lieutenant Chimiuo, whom I have 

 suggested may liave been one of the officers of tlie H.M.S. Herald. 



I took with me to Sunday Island copies of all the descriptions of 

 the known Kermadec shells, and I could find nothing on the island 

 answering at all to the description of II. Chimmoi. In the British 

 Museum I found specimens of the shell I have called Ptychodon psimtes 

 so labelled, and concluded they must be the original specimens, tliough 

 they disagreed with the original description as to size. I have, how- 

 ever, now found specimens which bear the label II. Chimmoi, and 

 which someone has marked ' Type ', and which agree with the 

 Pfeifferian description. I have carefully examined them and would 

 now suggest that the locality is quite erroneous. They are quite 

 unlike anything I have collected, and though I do not claim to have 

 absolutely obtained every mollusc, I cannot think that sucli a large 

 and conspicuous form should have escaped me. My suspicions seem 

 further confirmed in that two species about the same size were 

 contained in this typical lot, and the other one is also quite unrepie- 

 sented in my collection and is quite as unfamiliar as the typical 

 M. Chimmoi. 



Patdla modicella, Ferussac, var. vicinalis, Mousson. 



In the Journ. de Conch., vol. xxi, p. 112, 1873, Mousson described 

 as from Sunday Island, Kermadec Group, a shell he compared with 

 P. modicella, Ferussac, and only gave it varietal rank, but doubted 

 that it might be regarded as specifically distinct. He wrote : " Ces 

 differences consistent avec une forme generale assez analogue, en des 

 tours un pen plus arrondis," and his measurement read " diam. 3; 

 alt. 1-2 mm." 



Here, again, nothing agreeing with this description was found, 

 though the shell [ have called Pti/chodon Roi/amis suggested itself bj' 

 its size. Comparison with Patula modicella showed that this had no 

 relationship and could never be contrasted, and no other shell measuring 

 anything like 3 mm. was found. 



What can be the solution of these extraordinary puzzles ? I have 

 recorded our search for Ilelicarion Kermadecensis. Can it be that both 

 IIeli.v Chimmoi, Pfr., and Patula modicella vicinalis, Mousson, have 

 been exterminated or likewise driven to some last undiscovered 

 stronghold ? The suggestion seems preposterous, so that I simply 

 record here the facts that shells supposed to have been collected 

 by Macgillivray and Graelfe were not found by me, though I should 

 think I made much more extended and diligent search than either of 

 my predecessors. Can it be that either of these shells were collected 

 on one of the outside islands and characterize the former molluscan 

 faunula of the group ? 



Genus Pronesopupa, nov. gen. 



The small shell for which I propose the above name has greatly 

 perplexed me. It can be shortly characterized as a Nesopupa without 

 any apertural armour. When Pilsbry wi'ote upon the Pacific Pupoid 

 Shells (Proc. Acad. Nat. Sci. Philad.," 11)00, pp. 431-3) he introduced 



