bartsch: land shells of Palawan passage 



363 



Amphidro77ius versicolor Fulton is now known from Balabac, 

 Mantangule, Bancalan, and southern Palawan, all much larger 

 islands than those occupied by Amphidromus quadrasi Hidalgo. 



In spite of the great general variability of the color pattern, 

 certain phases of coloration prevail on the separate islands which 

 would enable one thoroughly familiar with these molusks to name 

 with a fair degree of accuracy the island from which a specimen 

 was derived. Measurements of a large series of specimens from 

 the various islands give the results shown in table 2. 



TABLE 2 



LOCALITY 



Balabac 



Bancalan 



Mantangule 



Palawan Passage 



Palawan, Brooks Pt 



Palawan, Mt. Landargung. 



GREATER 

 DIAMETER 



18.89 

 18.75 

 17.33 

 19.93 

 19.66 

 20.60 



The shell described by me^ from ' 'Palawan Passage" as Amphi- 

 drovius quadrasi palawanensis yield measurements that agree 

 nearest with those of Amphidromus versicolor everetti which comes 

 from southern Palawan, They also agree with this in haVing a 

 remarkably uniform color pattern and dark coloration both out- 

 side and within, but they lack the obsolete peripheral angle char- 

 acteristic of all the Palawan shells seen. It is unfortunate that 

 we do not have a definite island locality for them. 



The dark-colored race from the low lands of southern Palawan 

 will have to be known as Amphidromus versicolor everetti Fulton, 

 and it is more than possible that the shell described as Amphidro- 

 mus quadrasi solida Fulton from Palawan will prove to be simply 

 a color phase of this race. I have not seen specimens of it from 

 Palawan. The forms I called Amphidromus quadrasi solidus in 

 my paper from Balabac must now be placed with Amphiaromas 

 versicolor versicolor Fulton. The main coloration of Amphidro- 

 mus versicolor everetti Fulton is very similar to my Amphidromus 



5 Bull. 100, U. S. Nat. Mus., Vol. 1, pt. 1, pp. 39-40, pi. I, fig. 15, pi. 20, figs. 1, 4, 

 6. 9. 1917. 



