RANDOM NOTES ON NATURAL HISTORy. 



siblc that the so-called Western Painted 

 Tortoise, the Chry-emys manjinata Agassiz, 

 is found in Rhode Island waters. The dif- 

 ference between the two is very slight. 

 While C. jncta lias the anterior yellow bands 

 of the second lateral plates continuous with 

 the band of the second vertebral plate, C 

 marglnata has the' bands considerably sep- 

 arated. Specimens of both varieties have 

 been taken in Middleboro', Mass., though 

 in the few Rhode Island specimens I have 

 examined, no marked variation could be 

 found. 



8. Chelojmsguttatus (Sciiweigger) Cope. 

 (Nanemijs guttata Ag., Emys guttata 

 ScHNEiuEu.)' The Spotted or Speckled 

 Turtle is found as abundantly as the Painted, 

 and inhabits similar localities. Its distin- 

 guishing features are its black, yellow spot- 

 ted back, and yellow, striated, and black 

 blotched sternum. In size it is considerably 

 less tlian picta. 



These turtles are especially fond of warm 

 mud-ponds, from Avhich they crawl during 

 the day and crowd together on such float- 

 ing logs and partially protruding roots as 

 are always found in such situations ; the 

 slightest alarm, however, is sufficient to set 

 the colony in confusion, and, in a moment, 

 all have, with a splash, disappeared. 



As a result of several dissections, I wish 

 to correct a statement made .in the first 

 number of this series. The concavity or 

 convexity of the plastron is ua indication of 

 the sex. 



The Shell-Bearing Mollusca of Rhode 

 Island. 



HY IIORACK F. CARPENTER. 



Chapter XI. 



Genus Natica, (Adamson, 1757.) Lam. 

 Shell sub-globose or oval, spire slightly 

 elevated, aperture semi-lunar, a spiral col- 

 umella callus entering the umbilicus. Oper- 

 culum horny, with a calcareous outer layer. 



19. Natica pusii.la. Say. 

 Shell thin, sub-oval, cincrous or rufous, 

 sometimes with one or two obsolete, dilated, 

 revolving bands ; columella with a white 

 callus pressed into the umbilicus, almost 

 filling it, leaving only an arcuated,' linear, 

 vertical aperture. Length, \ inch. 



Described l)y Say, Jour. Ac. Nat. Sc, 

 II. 257, 1822. 



Distr., Vineyard Sound to Northern 

 Florida. Georgia (Couper). Fort Macon, 

 N. C. (Coucs). Gardiner's Bay, L. I. (S. 

 Smith). Vineyard Sound and Buzzard's 

 Bay, 2 to 10 fathoms (Verrill). 



Genus Lunatia, Gray, 1847 (Globularia, 

 Sw.). 

 Shell sombre-colored, covered with a thin, 

 dark epidermis ; sub-globose; spire ele- 

 vated ; aperture semi-lunar ; umbilicus wide ; 

 operculum corneous. Inhabits the cold and 

 temperate zone. 



20. Lunatia herds, Say. 

 Syns. : 



Natica hcros. Say, Gould, DeKay, etc. 



Ampullaria borealis, Valenc. 



Lunatia heros, Stimp., Dall., Tryon, Per- 

 kins, etc. 



Shell sub-globose ; ash-colored or brown- 

 ish, shining Avhen divested of its thin, yel- 

 lowish epidermis ; whorls five, very convex, 

 slightly flattened near the suture ; lip sharp 

 above, becoming rounded and thicker as it 

 descends, and at the umbilicus sliglitl,y ex- 

 panded ; a thin layer of enamel completes 

 the rim of the aperture ; the interior of the 

 mouth of the shell is of a delicate, some- 

 times iridescent chestnut color, with a yel- 

 low margin ; umbilicus large, round ; oper- 

 culum corneous. Length 3 to 5 inches, 

 breadth about 3i inches. It is the largest 

 species known, and inhabits from New Eng- 

 land to Nova Scotia. It is very abundant 

 and of large size on the coast of Maine, 

 and is collected and sold for food in the 

 markets in Portland. It is not common 

 south of Cape Cod, and when found is 

 smaller than those found north of it. Its 

 northern limit in Rhode Island is the sandy 

 shore between Warren and Nayatt Light- 

 house. Described bv Say, Journ. Ac. Nat. 

 Sc. PMla., II. 228,1822. 



21. Lunatia triseriata, Say. 



Syns. : 



Natica triseriata, Sa}', Gould, DeKay, 

 Philippi. 



Lunatia heros, var. Verrill. 



Shell ovate-globose, of a yellowish-whito 

 or ashy color ; whorls five, convex, covered 

 with lines of growth ; spire elevated ; aper- 

 ture ovate; lip sharp and white within; 



