[Illustration: FIG. 1. Map of southeastern United States showing record stations of _Trionyx muticus calvatus_ (solid symbols) and _Trionyx m. muticus_ (open symbols). Circles indicate specimens examined; triangles indicate records in the literature. The question mark refers to a specimen bearing catalogue number 17236 in the collection of Tulane University (see comments on page 524 concerning No. 17236 from the Amite River).] _Range._--_Trionyx m. calvatus_ is known from the Pearl, Pascagoula and Escambia river drainages and is to be expected in the Tombigbee-Alabama river drainage (Fig. 1). Tinkle (1958:41, fig. 53, stippled) has indicated the probable range of _calvatus_. This subspecies is unknown from the Mississippi and Tennessee river drainages, which are inhabited by _T. m. muticus_. The western limit of distribution is the Pearl River drainage and probably those streams of the Florida Parishes of Louisiana that drain into Lake Ponchartrain. The most easterly record of occurrence for _T. m. calvatus_ is in the Escambia River drainage; the eastern extent of geographic range is not known. I have seen three preserved young turtles having the characteristic spotted pattern from the Pascagoula drainage in eastern Mississippi. These specimens are uncatalogued and in the collections at Mississippi Southern College, Hattiesburg, Mississippi. There is a specimen of _T. m. muticus_ labeled as from Mobile, Alabama (MCZ 1596), for which I believe the locality datum is incorrect. It is a young turtle having a well-defined pattern on the carapace and is without doubt a representative of _T. m. muticus_. Mobile is in the large drainage basin, of the Tombigbee, Black Warrior, Coosa and Alabama rivers, which is between the Escambia and Pearl rivers. Yarrow (1882:28) reported a specimen of _Amyda mutica_, USNM 11630, from Gainesville, Florida. This record was questioned by Cahn (1937:179), and has been disregarded by subsequent authors. Stejneger (1944:23) lists this specimen number with uncertainty from Mt. Carmel, Illinois. The exact geographic provenance of this specimen is seemingly unknown. _Habitat._--I have collected eggs of _T. m. calvatus_ on sand banks of the Escambia River, Florida. The Escambia River has a sand-gravel bottom, extensive sandy banks, a moderately-rapid current, and is flanked by a thick riparian forest. It is approximately 80 feet wide with fallen trees and brush intermittently emergent along the shoreline. The sand bar-habitat along the Pearl River has been mentioned by Anderson (1958:212). All records thus far are from lotic habitats.