Boone, Mollusca, Cruises of "Eagle" and "Ara," 1921-28 201 



Measurements : Long diameter 75 mm., short diameter 46 mm. 

 Anterior valve : Regularly convex, entire surface covered by fine, 

 radiating, subobsolete riblets that appear as almost interrupted series 

 of granules. Twelve slits are present. 



Intermediate valves: The central areas of these valves are finely 

 sculptured, with close longitudinal riblets separated by deeper inter- 

 stices, about 80 riblets are on the fourth intermediate valve. The lat- 

 eral areas are well defined, but little rounded, sculptured by about 

 the lines of fine, radiating obsolete riblets, each consisting of a wavy 

 line, formed by the irregularity of the rib; interstices well defined, 

 quite porous. One slit is present in each valve. The sutural plates 

 are wide, the sinus square, finely toothed. 



Posterior valve: With the umbo very near the posterior margin, 

 the central region short, regularly striated with fine riblets separated 

 by deeper interstices, as in the preceding valves ; the region behind the 

 umbo sloping, the postlateral region evenly rounded, sculptured by 

 wavy, concentric lines of fine radiating subobsolete riblets separated 

 by porous interstices. Fourteen slits are present. 



Girdle : In the preserved specimen 9 mm. wide, shining black, paved 

 with strong, imbricating scales; an average scale has a rhomboidal 

 contour with the dorsal surface convex; some are less rhombic in 

 outline. 



References: Chiton latus Sowerby, Tankerville's Catal. of Shells, 

 Appendix, p. 5, Jan., 1825 (not of Lowe, April, 1825, nor of 

 Guilding, 1829).— D all, Proc. U. S. Nat. Mus., vol. 37, p. 247, 

 1910. 

 Chiton magnificus Deshayes, Diet. Class, des Sci. Nat., vol. XII, p. 

 455, 1827; Encycl. Meth., p. 680. — Lamarck, Anim. sans Vert., 

 Deshayes Ed., vol. 7, p. 498, 1836.— Reeve, L., Conch. Icon., pi. 1, 

 fig. 3/ 



Section: BADSIA Gray. 

 Chiton goodallii Broderip. 



Plate 126. 



Type : Collected at James Island, Galapagos, by Hugh Cuming ; the 

 older specimens were found in exposed situations; the younger indi- 

 viduals under stones and ledges of rock at low tide. Depository not 

 cited ; type first in the Hugh Cuming collection. 



Distribution : Galapagos Islands ; Cocos Island. 



