SYKES: NEW HAWAIIAX NON-MAKINE MOLLTJSCA. lol 



Beck proposed Microcystis in 1837' as a section of Nanina, Gray, 

 and he placed in it six species in the following order : — 



1. pellicula, Beck. This appears to be of uncertain identity, but 



is most probably a Cape of Good Hope species near Zimjis 

 Natalensis (Pfr.). 



2. trifasciella, ^ec^ = IIelix Cubensis, Pfr. 



3. pictella, Beck=irelix Cubensis, Pfr. 



4. ornatella, Beck. 



5. filieeti, Beck = Helix Adamsi, Pfr. 



6. amcenula, Beck = ? M. ornatella, Beck, var. 



"We have first to settle whether Microcystis is worthy of retention 

 in our nomenclature, and then what species should stand as its type. 

 The principle which I would suggest should be applied is, that where 

 a genus is put forward in an old catalogue of this kind, with no special 

 named type, but a somewhat heterogeneous list of species, it shoidd 

 only be retained if one of two conditions be fulfilled, namely, that 

 it has either been properly adopted by some subsequent author prior 

 to any other name being suitably proposed, or where no other name 

 at all has been given to the group. Further, the first identifiable 

 species, not belonging to any other genus, should be the type ; or, 

 the first species, if the genus has been broken up, so placed by the 

 author dividing the group, provided, of course, it be originally in 

 the genus. Now, how do we stand with regard to Microcystis ? 



Albers,''* in 1850, properly adopts this genus, placing as his first 

 species one not included by Beck ; his second, however, being 

 M. ornatella, Beck. 



Morch,^ in 1852, gives M. ornatella as his first species; he created 

 at the same time the genus Cysticopis for ZT. Cubensis, Pfr. { = irifasciella 

 and pictella of Beck). 



Beck's first species being of uncertain identity, I would therefore 

 suggest that ornatella be treated as the type of Microcystis. Now 

 these small Zonitoids hardly fit into the same genus as this species, 

 and therefore some other generic title is requii'ed for them. 



It appears to me that Macrochlainys, Benson,* is the most suitable. 

 The advantages and disadvantages of retaining this name in nomen- 

 clature have been so recently discussed by Colonel Godwin-Austen,^ 

 that I will not enter into the subject here, beyond saying that his 

 reasons for its retention appear sufticiently convincing. The t}q:>e is 

 M. Indica, Benson, which has been sometimes improperly contused 

 with the Helix vitrinoides, Deshayes, and is even now slightly un- 

 certain specifically : there is no doubt, however, that it agrees with 

 what is usually accepted as Macrochlainys. Whether our small forius 

 are in accord with the typical group of this genus anatomically, 



1 Index INIoll., p. 2. 



2 "Die Ileliceeu," p. 59. 

 » Cat. Voldi, 1852, p. 2. 



* Joxirn. As. Soc. Bengal, vol. i, 1832, pp. 13, 7(). 

 ^ " Mollusea of India," vol. i. 



