86 THE NAUTILUS. 



Lottia Antillarum Sowb., Reeve, Conchol. System.. ])1. cxxxvii, 

 f. 4 (printed from same plate as Sowerby's Genera) 1842. 



Patella tenera C. B, Adams, Proc. Bost. Soc. N. H. ii, p. 8 (1845). 



Patella tenera Ad., Reeve, Conch. Icon. fig. 104. 



Patella Candeana Orb., Moll. Cuba, ii, p. 199, atlas pi. 25, 

 figs. 1-3. 



Acmcea Candeana Orb., Dall, Catal. Mar. Moll. S. E. U. S., p. 

 159. 



Acmcea Candeana Orb., Pilsbry, i\Ianual of Concbology, xiii, p. 

 38, pi. 5, figs. 91-95, and pi. 42, figs. 92-95. 



f Patella (Acmcea f) elegans Philippi, Abbild. u. Beschreib. iii, 

 p. 34, Patella p. 6, pi. 2, fig. 2 (1846). 



? Not P. antillarmn Sowb., Philippi, Abbikl. iii, Patella pi. 2, 

 fig. 12. 



Acmcea Antillarum is found throughout the West Indies, from the 

 Bahamas and Southwest Florida to Tobago. 



NOTES ON UNIONID.ffi:. 



BY CHAS. T. SIMPSON. 



The November number of the Nautilus seems to be devoted 

 mostly to Unios, and to me is an exceedingly interesting issue. 



Lea's classification of the Unionidce was almost wholly an artifi- 

 cial one, and I believe he instituted it for convenience in working, 

 just as Linnaeus founded the artificial system of classification in 

 botany. Both these great pioneers in science recognized the natural 

 systems, and probably used these as makeshifts. All through the 

 latter part of his Avritings, Dr. Lea acknowledged the fact that the 

 Unionidce were divisible into natural groups. To some capable 

 student of the future is reserved the task of determining these 

 groups and assigning the species to them. The accomplishment 

 of this will be well worth a working lifetime of careful and honest 

 study. 



Mr. Geo. W. Dean claims to be able at sight, to refer to its 

 proper species any specimen of either Unio luteolus or radiatus. I 

 confess that this is more than I can do, and I have handled many 

 thousands of specimens of both, collected from the entire territory 

 inhabited by these familiar forms. The distinguishing features 



