392 MOLLUSKS OF THE GALAPAGOS — STEARNS. 



CU'ims TROPHON Montrort. 

 60. Trophoii ? xanthostoma Hrod. 

 = T. Perurianus Lesson. . 



One boiit'li shell, junior, in j^ood condition. Hood Islantl. (Mns. 

 No. 102351). 



Sublamily Purpurin^. 



Genus PURPURA l?rii,<,Miiere. 

 61. Purpura patula Liiine. 



Connnou on the beaches, etc. 

 James, Indetatijiable, and Hood ishmd.s. Several fresh specimens 

 from the lirst place (Mns. No. 102270), and numerous dead shells 

 from the other islands. Also at Chatham Island, in Jones's eollectiou. 



Section PURPURELLA Ball. 



62. Purpura (Purpurella) columellaris, Lamarck. 



Common alono- the shores, etc. 



Hood, James, Chatham, Charles, Duncan, and Indefatigable islands; 

 quite large and heavj^ shells from the latter (Mus. Nos. 10237(5, 

 102311, 10231S, 102282, and 122113). From Hood one solid specimen 

 measured 3 inches, and the smallest adult only thirteen sixteenths of 

 au inch in length. The examples from James Island vary considera- 

 bly in the elevation of the spire. 



Section PLANITHAIS Bayle. 

 63. Purpura (Planithais) planospira Lam. 



Beaches, abundant and frequently of large size. 



Hood, Indefatigable, and James islands (^lus. No. 102377); quite 

 numerous on the two last islands, where it often occurs with the 

 surface burrowed by some form of PhoJad or Lithodomus. This species 

 appears to be rather insular in its distribution. It is abundant and 

 tine at Socorro Island, one of the Ilevillagigedos group, which is 

 situated in latitude 180 35' north, and longitude 111° west of Green- 

 wich, distant from IMazatlan something over 300 miles, in a south- 

 westerly direction, and about 240 miles south from Cape St. Lucas. 

 The Galapagos examples are often exceedingly solid and heavy. 



Section THALESSA H. & A. Ad. 



64. Purpura (Thalessa) inelo Duclos. 



Beach shells, common. 



James, Duncan, Hoods, and Indefatigable islands. Closely related 

 to the Antillean <1c}toi(h((, and suggestive of a common ancestry. Dr. 

 Jones collected the above at Chatham IsUmd. 



