354 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



PLATE 59. 

 Tatraclita squamosa stalactifera Lamarck. Page 254. 



FIG. 1. Abaco, Bahamas. Cat. No. 48056, U.S.N.M. 

 la, 16. Tergum and scutum of the same, Cat. No. 4S056. 



2. St. Thomas. Cat. No. 48057, U.S.N.M. 



3. Porto Rico. Cat. No. 26360, U.S.N.M. 



4. San Juan del Sur, Nicaragua, A.N.S.P. 



5, 5o, 5ft. Mazatlan, Mexico. Cat. No. 48058, U.S.N.M. 



6, 6a, 66. Form floridana Pilsbry. Type. Lake Worth, Florida. No. 1444, 



A.N.S.P. Page 255. 



PLATE 60. 



FIGS. 1-ld. Tetraclita squamosa milleporosa Pilsbry. Albemarle, Galapagos. 



Cat. No. 48059, U.S.N.M. Type. Page 257. 



2. Tetraclita s. squamosa form confinis Pilsbry. St. Georges Island, 



Gulf of California. Cat. No. 48089, U.S.N.M. Page 255. 



3, 3a, 36. Tetraclita squamosa panamensis Pilsbry. Panama. Cat. No. 48061. 



U.S.N.M. Type group in lateral and basal views, and a tergurn. 



Page 256. 



PLATE 61. 



FIG. .1. Tetraclita squamosa rubescens Darwin. California. Cat. No. 6652, 



U.S.N.M. Group on a piece of sandstone. Page 257. 



la, 16. T. s. rubescens. Cat. No. 6652, U.S.N.M. Basal view of entire 



specimen and lateral compartment of another. 



Ic, Id. T. s. rubescens. Cat. No. 6652, U.S.N.M. Tergum and scutum, 

 le. T. s. rubescens. Cat. No. 6652, U.S.N.M. Articulating face of a 



radius. 

 2. T. s. rubescens, form elegans Darwin. Cat. No. 58062, U.S.N.M. 



Page 258. 



3-3c. Tetraclita radiata (Blainville). Opercular valves of a specimen 

 from St. Thomas, West Indies. All drawn to same scale. 



Page 259. 



4. T. radiata. Apical view of specimen from a Cape Cod whaler. 

 Diameter of largest individual of the group, 7.5 rum. 



PLATE 62. 



FIG. 1. Chelonibia testudinaria (Linnaeus). Iguana Cove, Albemarle, Gala- 

 pagos. Cat. No. 48069, U.S.N.M. Page 264. 



2. C. testudinaria. Florida. Cat. No. 48070, U.S.N.M. 



3. C. testudinaria. San Luis Gonzales Bay, Gulf of California. 



4. C. testudinaria. Brentons Point, Newport, Rhode Island. Cat. No. 



48071, U.S.N.M. 

 5, 5a. Chelonibia manati crenatibasis Pilsbry. Cat. No. 48072, U.S.N.M. 



Page 266. 



6. Chelonibia testudinaria. Scutum and tergnm, the chitinous articu- 

 lar ridge removed. Enlarged. Page 263. 

 7-7a. Chelonibia manati lobatibasis Pilsbry. Type. Osprey, Florida. 

 Fig. la enlarged. Page 263. 



