THE NAUTILUS. 85 



a shell and operculum under the name of D. leithii from Cali- 

 fornia, where it has not since been recognized, but probably is a 

 Lower Californian shell. 



Alaba supralirata Carpenter, was described in the Mazatlan 

 Catalogue and is an abundant Lower Californian shell. An ex- 

 amination of a dry specimen shows it to have an operculum 

 paucispiral and like that figured for Diala leithii Smith, with no 

 spur or outstanding spiny process. The radula is not quite like 

 that figured by Troschel. The rhachidian tooth has a squarish 

 base with three rounded cusps, the central one larger than the 

 others. The extreme minuteness of the object and the tangled 

 condition of the radula did not enable me to determine the form 

 of the stems of the inner laterals, but the outer ones and appar- 

 ently the others were slender, the distal ends forming a semi- 

 circular curve with extremely fine serrations on the edge. The 

 radula and operculum of Alaba have not previously been de- 

 scribed. 



The shell listed by Carpenter as Diala marmorea though shaped 

 and colored like some of Adams' Dialas, does not belong to the 

 genus. It has the operculum and radula of Barleeia but differs 

 in having a smooth nucleus while that of Barleeia rubra is 

 thimble-pitted. The rhachidian tooth of marmorea is more 

 squarish than that of B. rubra as figured by Troschel, and has 

 five rounded cusps, the middle one larger. The styliform pro- 

 cess of the operculum is remarkably long in proportion to the 

 size of the operculum. Whether the difference in the nuclei 

 warrants a distinctive name for B. marmorea need not now be 

 decided. 



OBSERVATIONS OH LIVING 0ASTEBOPODS 07 NEW ENGLAND 

 B; Edward S. Mtr., Pubody Kuieum, pp. 1-29, plat. MX. 



BY PAUL BARTSCH 



Two years ago Professor Morse published his paper " Ob- 

 servations on Living Lamellibranchs of New England ", in 

 the Proceedings of the Boston Society of Natural History, 

 (Vol. XXV, No. 5) in which forty-eight species are described 

 and figured. 



