354 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



Plate 59. 



Tatraclita squamosa stalactifera Laiimrck. Page 254. 



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

 la, lb. Tergum aud scutum of the same, Cat. No. 48056. 



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



3. Porto Rico. Cat. No. 26300, U.S.N.M. 



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



5, 5a, 5b. Mazatlan, Mexico. Cat. No. 48058, U.S.N.M. 



6, 6a, Qb. 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. 48080, U.S.N.M. Page 255. 



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



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



Page 256. 



Plate 61. 



Fig. 1. Tetraclita squamosa ruhescens Darwin. California. Cat. No. 6652, 



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



la, lb. T. s. ruhescens. Cat. No. 66-52, U.S.N.M. Basal view of entire 



specimen and lateral compartment of another. 

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

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



radius. 

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



Page 2.58. 

 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 mm. 



Plate 62. 



Fig. 1. Chelonibia testudlnaria (Unnxns) . Iguana Cove, Albemarle, Gala- 

 pagos. Cat. No. 48060, 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. Chelonihia manati crenatibasis Pilsbry. Cat. No. 48072, U.S.N.M. 



Page 266. 

 6. Chelonihia testudinaria. Scutum and tergum, the chitinous articu- 

 lar ridge removed. Enlarged. Page 263. 

 7-7a. Chelonihia manati lohatihasis Pilsbry. Type. Osprey, Florida. 

 Fig. 7a enlarged. Page 263. 



