The Nautilus. 



Vol. XXIII. DECEMBER, 1909. No. 7 



ON SOME DEFORMED CYTHMh. TIGRIS FROM THE COLLECTION OF 

 A. DA COSTA GOMEZ. 



BY H. A. PILSBRT. 



Many years ago the conchologists of Europe were astonished to 

 receive from New Caledonia certain cowries which had the aspect 

 of such well-known species as C. moneta, lynx and mappa, yet dif- 

 fered by the produced and calloused ends, attended with more or 

 less thickening of the enamel and a degree of melanism, or clouding 

 of the coloi'-pattern. Several of these shells were named as distinct 

 species by Crosse, Marie, Montrouzier and others. British writers 

 generally did not admit their validity, considering them pathologic 

 forms, due to some diseased condition of the mantle, a view ridiculed 

 by Crosse in his witty review of G. B. Sowerby's monograph of 

 Cyprsea in the Thesaurus Conchyliorum. Mr. S. Raymond Roberts 

 in his monograph' treats them as varieties. M. Ph. Dautzenberg has 

 recently discussed these forms, figuring several of them.'' The cause 

 of the rostration and hypertrophic deposit of calcareous material has 

 never been really settled, so far as I know, by observations on the 

 living animals. The occurrence of so many forms modified in the 

 same manner, in one locality, points to the action of me specific 

 cause which might perhaps be recognized by an observer on the spot. 

 It seems, however, that the modifications do not have racial signifi- 

 cance. A somewhat similar formation characterizes some un- 

 doubtedly " good " species elsewhere, such as C. scottii and G. 

 prohhmatiea. 



^ Manual of Oonchology, Vol. "VII. 



2 Journal de Conchyliologie, 1906, p. 263. plate ix. 



