217 



NEW GENEEIC NAMES AND NEW SPECIES OF MARINE 

 MOLLUSCA. 



By Tom Iked ale. 



Bead 10th May, 1912. 



PLATE IX. 



To this periodical I have already contributed papers originated 

 tlirougli the study of a collection of shells made at the Kerniadec 

 Islands, and in tliis essay I describe a few of the novelties there 

 obtained, and also propose some new generic names. The determination 

 and description i new specific forms is a necessary evil, but the 

 attempt to generically place even common shells seems to be an 

 unnecessary evil to the majority of writers, and one which has been 

 constantly neglected. 1 noted (this periodical, vol. ix, p. 70): 

 ■'Furthermore I have found great, difficulty in generically locating 

 such well-known species as I)nipa{?) chaidea, Duclos, and Galeropsisi^) 

 monodo7iia, Quoy & Gaimard." Prolonged study has convinced me 

 of the inaccuracy of the continued attachment of the preceding, with 

 others, to genera with which they have little in common, and I later 

 wrote (vol. ix, p. 320) : "In recent yeais scarcely any scientific 

 worker has described a new minute shell without carefully detailing 

 the apical characters, and using them for classificatory purposes. 

 Yet these same workers have been content to class larger well-known 

 shells in an almost Linnean fashion." 



In attempting to work through this collection I have been 

 impressed with factors that have militated against the accurate and 

 easy determination of the Indo-Pacific Marine Mollusca: firstly, the 

 lack of series, showing variation, from almost any locality, and 

 especially the almost entire absence of individuals showing the 

 juvenile characters : this is most noticeable when it is realized that 

 the majority of the common littoral Indo-Pacific molluscs are so 

 abundant that long series of many forms could be easily obtained in 

 a single day, covering most stages from the very young to adult. 

 We are thus ignorant of the juvenile stages of very many of the 

 commonest molluscs, and know tlie development only in rare cases, 

 and until such are fully known all our higher groupings must be 

 most imperfect, and in many cases also inaccurate. Secondly, it is 

 no longer a possibility to correctly work out such a collection as mine 

 without practically monographing each genus, more certainly as the 

 monographs in the earlier volumes of Tryon's Manual of Couchology 

 are useful only as works of reference to literature, the malacological 

 matter being quite unreliable. I am convinced that all future 

 workers, to produce any lasting results, must undertake monographic 

 studies, and moreover must study series, note variation, also determine 

 the sub-species from such series, and discriminate between species, 

 sub-species, and varieties. I foresee the time when there will be 

 more genera, fewer species, and more sub-species, with entire 

 elimination of varieties. These latter may interest non-scientific 



