bartsch: land shells of Palawan passage 361 



ZOOLOGY. — The land shells of the genus Amphidromus from the 

 islands of the Palawan Passage.^ Paul Bartsch, U." S. 

 National Museum. 



JMy paper on The Philippine Land Shells of the Genus Amphi- 

 dromus- has had the usual effect of stimulating collectors to trans- 

 mit their shells to the United States National Museum for classi- 

 fication. In this instance we have been exceptionally fortunate 

 in receiving a large sending of carefully labeled specimens col- 

 lected by Mr. C. M, Weber, in the islands of Palawan Passage. 

 These greatly needed shells throw a flood of light on the systematic 

 problem of the complex that inhabits these islands and make it 

 possible to give a positive statement about them. It will be 

 remembered thatti was forced to say in the paper above referred 

 to: "I am quite perplexed by the following species [Amphidromus 

 qiiadrasi] and feel at a loss as to the treatment that should be 

 accorded to it." 



iVIr. Weber's material shows that on some of the islands off 

 southern Palawan these mollusks present a most remarkable 

 range of color variation and, what is more, show that similar types 

 of coloration occur upon several islands. The present collection 

 establishes beyond a doubt the fact that no matter how interest- 

 ing they may be from a breeder's standpoint, systematically con- 

 sidered these color phases have no more significance than the uni- 

 color, unicincta, bicincta, tricincta, amd quadricincta forms of Heli- 

 costyla ovoidea which I have found in a single brood of that species. 



The group breaks readily into two divisions. In the first 

 groop the tip is always white and the early whorls are flesh-colored, 

 turning gradually to yellow which becomes intensified as the shell 

 increases and is darkest immediately behind the aperture, or the 

 yellow may be replaced Jby green. A very narrow light line marks 

 the summit of the turns below which a deep-maroon band en- 

 circles the whorls ; the base at the columellar border is also edged 

 with this color, while the lip is always white. This is Amphidro- 

 mus quadrasi Hidalgo. This species, so far, is known from three 

 islands, Candaraman, Coxisigan, and Bekin. 



^ Published by permission of the Secretary of the Smithsonian Institution. 

 ■' Bull. 100, U. S. Nat. Mus., Vol. 1, pt. 1, pp. 1-47, pi. 1-22, 1917. 



