1871] MR. HARPER PEASE ON POLYNESIAN LAND-SHELLS. 4/1 



most essential difference between the two descriptions is, that M. 

 oryza is described as having but three plaits on its outer lip, while 

 M. mucronatus, Gld., has eight ; the plaits decrease in size as they 

 recede from the base, so that on many specimens the posterior ones 

 are quite small or become obsolete ; the mucronation is indistinct on 

 most specimens, the basal striae constant. I would add to the de- 

 scriptions that the spire is very finely striate longitudinally, and the 

 last whorl slightly depressed posteriorly, giving the spire a slender 

 appearance. The species is certainly distinct, and not a variety of 

 M. luteus, Quoy, as suggested by Dr. Gould. The latter species I 

 have in all stages of growth from the same locality. 

 The following synonym was omitted above. 



Atropis producta, Pse. 



Realia producta, Pse. Proc. Zool. Soc. 1864, p. 673. 



Hydrocea raiatensis, Mouss. Journ. de Conch. 1869, p. 67. 



Hah. Insulse Raiatea et Tahaa. 



On comparison of a large number of specimens, the above will be 

 found to vary considerably. The type is represented on the island 

 of Bolabola by A. bolabolensis, Dohm, and at Tahiti by A. terebralis, 

 Gld. A. elongata, Pse., inhabiting Raiatea, is more distantly re- 

 lated to it. 



Catalogue of Genera and Species. 



The whole number of species of land-shells known as inhabiting 

 Polynesia is 626. 



In the following Catalogue the Helicterince are omitted, a list 

 having been lately published in the Society's 'Proceedings' (1869, 

 p. 644), to which but one species has been added since. 



The genera and number of species of each are as follows : — 



Inoperculata. 



Helicterince, 223. Partula, Fer., 63. 



Vitrina, Drap., 2. Vertigo, Mull., 19. 



Succinea, Drap., 26. Rhysota, Alb., 1. 



Truella, Pse., 3. Hyromia, Risso, 1. 



Catinella, Pse., 2. Trochomorpha, Alb., 21. 



Carelia, H. & A. Ad., 6. Endodonta, Alb., 10. 



Chlorcea, Alb., 1. Pitys, Beck, 33. 



Tornatellina, Beck, 18. Microcystis, Beck, 4. 



Lamellina, Pse., 2. Helicopsis, Beck, 30. 



iBulimus, Scop., 2. 1 Helix, Linn., 10. 

 Stenogyra, Shutt, 5. 



Operculata. 



Diadema, Pse., 3. Palaina, Semp., 15. 



Cyclophorus, Mont., 1. Moussonia, Semp., 1. 



Ostodes, Gld., 5. Cyclostomus, Mont., 1. 



Registoma, Hass., 1. Omphalotropis, Pfr., 16. 



Pupina, Vign., I. Atropis, Pse., IS. 



