3« 



Various additional suggestions have been offered as to a 

 suitable taxonomic designation for these demes of polytypic 

 species, among others " microsubspecies" (Huxley, 1940); 

 "microraces" (Dobzhansky, 1937); "subsubspecies", (Gold- 

 schmidt, 1945), but have not been found entirely satisfactory. 



Dr. J. Gordon Edwards (1954) has suggested that as a sub- 

 stitute for the term *' form", which is meaningless apart from 

 some correlative context, as well as for the other above men- 

 tioned expressions, the term '*morph". This has the advantage 

 of consisting of a single word instead of a compound expres- 

 sion, thus paralleling the terms genus and species. This also 

 serves to replace the vague term "form*' with a word of Greek 

 origin, which is meaningful, but has not previously been used 

 except as a significant element in a number of biological terms, 

 such as morphology, morphogenesis, etc. 



According to the suggestion of Dr. Edwards the proposed 

 units would not be regarded as trinomials subject to the law 

 of priority, but could be designated by explanatory spatial, 

 genetic or ecological terminology by adding a suitable prefix. 



Since the above described system seems well designed to 

 give descriptive expression to the wide range of variants met 

 with in the study of Thais material, it has been adopted for 

 use in the present paper. The several morphs will be distin- 

 guished numerically and by pinpointing as closely as possible 

 their microgeographical localization. 



ORIGIN OF THE LOCAL RACES 



The group of muricids constituting the subgenus Nucella 

 {Polytropa according to some authors) of the genus Thais 

 appears to have had its early development in the North Pacif- 

 ic area during the late Miocene, and undergone a considerable 

 expansion and differentiation during the Pliocene and Pleisto- 

 cene. According toGrant and Gale (193 1) the stock represent- 

 ed by the modern Thais lamellosa has been in continuous ex- 

 istence during this entire time. 



