^^1893!"'] PROCEEDINGS OF THE NATIONAL MUSEUM. 393 



65. Purpura (Thalessa) callaoensis Gray. 

 = CoraUiophilu caUaoensis Auct. 



• Fresh specimens, beach. 



Charles Island, three examples (Mns. No. 102313). In Tryon's Man- 

 ual the above is grouped with (Joralliophila. Common at Manta, coast 

 of Ecuador. 



Gemis MONOCERAS Lamarck. 



( = ACANTHINA F. de Waldlieiin). 



66. Monoceros grande Gray. 



Beach specimens. 



James and Indefatigable islands; apparently rare; the distribution 

 of this species seems to be confined to the Galapagos group; the 

 national collectiou contains a good example (No. G0719), probably 

 collected by Dr. Habel ; the particular island not stated. 



Subfamily T^nioglossa. 



Family TKITONIID^.. 

 Genus TRITONIUM Cnvier. 

 Section COLUBRARIA Schumacher. 

 67. Tritonium (Colubraria) Sowerbyi Reeve. 



The basal whorl, of what I regard as the above species, was obtained 

 at Indefatigable Island (Mus. No. 117976). Reeve credits the above 

 (6 fathoms sandy mud, Cuming), as well as a related form T. reticulatus 

 to the Galapagos group. The fragment before me is in fair condition 

 so far as color and sculpture go. While it evidently has general rela- 

 tions with T. testaceus Morch {=r^(listorU(s and ohscurus, Tryon pars.), 

 it is much more finely sculptured and less rugged iu its general facies 

 than the latter; it also somewhat resembles T. reticulatus Blve., 

 [=intertextus Rve.), but is a more solid shell than that species. Both 

 reticulatus and testaceus are found in the Antillean-Caribbeau region. 

 As many marine species are common to the waters on both sides of 

 Middle and South America, and many of the Tritons have an exceed- 

 ingly wide geographical range, it would not be especially remarkable 

 if either of the above were detected on the west side. Reeve has 

 credited recticulatus to the Galapagos, but I am inclined to think that 

 a small example of ISoicerhyi is what that author had before him. The 

 sculpture of the fragment agrees with the description which Reeve has 

 given as characterizing Sowerhyi, and though the fragment is without 

 the general color or markings of either recticulatus or Sowerbyi, in my 

 judgment it should be assigned to the latter rather than described as 

 new. In the Colubraria grouj) of Tritons color is not a constant 

 character, and many of the species, to my knowledge, are colorless or 

 nearly destitute of color markings. 



