592 PROCEEDINGS OF THE ACADEMY OF [Auo". 



ON CERTAIN RHACHIGLOSSATE GASTROPODA ELIMINATED FROM THE 



AQTJILLID^. 



BY H. A. PILSBRY AND E. G. YANATTA. 



Among the smaller species described Iw the older authors as "Tri- 

 tons," and referred by Tryon and others to the subgenus Epidromus, 

 there exists some diversity in shell characters, and a much greater 

 difference in the soft anatomy. Morch many years ago eliminated 

 his Muricid genus Aspella from this assemblage, and Kesteven, in an 

 able and interesting paper, has recently shown an Australian species, 

 Triton speciosus Angas, to belong to Trophon, figuring its operculum 

 and teeth. ^ 



Another Muricid genus is represented by Triton bracteatus Hinds, 

 and its allies, characteristic and widespread littoral Polynesian species. 

 This group may be called 



MACULOTRITON Dall.= 



The shell is acuminate-oblong, longitudinally plicate and spirally 

 tuberculate-lirate, with a smooth trochoidal nucleus of about 3+ whorls. 

 Aperture ovate, the outer lip thick, dentate within, and strengthened 

 by a rounded varix outside, another varix often developed opposite 

 it on the last whorl. Anterior canal open, very short. A small pos- 

 terior sinus is defined by a low callous on the parietal wall. Opercu- 

 lum with basal nucleus. 



1 Proc. Linn. Soc. N. S. Wales for 1902, p. 479, fig. 3. 



=> In a paper issued last February, one of the'present authors suggested that 

 Colubraria hchum., which had always been associated with the xlnioglossate 

 Triton, might prove to be Rhachiglossate, and remarked that "a series of An- 

 tillean and Pacific species referred to this division bv Trvon and others of 

 which decapitatus Reeve and bracteatus Hinds are typical, belongs to the Rhachi- 

 glossa, as Mr. Vanatta and the writer will elsewhere show." In a paper on 

 the Tritons and Frog-shells just issued. Prof. W. H. Ball adopts but does not 

 define a fanuly Colubrariidce to include Colubraria, the groups we had indicated 

 as Rhachiglossate and one or two others. He anticipates the appearance of 

 the data promised by us, by giving names to the groups we had indicated as 

 Rhachiglossate. It remains, therefore, for us to substitute in our proof-sheets 

 the names given by Dall for those we had written, and to e.xpose the true char- 

 acters and family relationships of the gastropods in question 



As to the "Family Colubrariida'," the typical genus Colubraria is as yet known 

 by the shell alone. The other groups referred to it by Dall, of which the dentition 

 is known belong without any doubt to the Aluricidce and Buccinidce. Is science 

 advanced by the formation of family groups upon such grounds? 



