[II ] 



77. Pleurocera verrucosa. Ellipsoidal, top very obtuse, base of the opening ob- 

 tuse, inside lip ihickl) plaited; four spires, the two last flattened, n otin i .arge, 

 '.villi several rows of warts, back of the opening wrinklt <!.-- Length aL u' 'wo. 

 thirds of an inch, not quite double the breadth ; colour olivaceous bruun, op r, 'g 

 whitish. It lives in the lower pails of the Ohio. This genus which con'.' us near- 

 ly twenty species of fluviaiile shells, was described in my 70 N. G. Aui als, &.C. 

 I •iave discovered already about one hundred and eighty species of fluviatile and 

 land shells in the United States. 



IX CL VS8. POLYPI A. —THE POLYPS. 

 XIX. X G Mxuji ism*. Body free, globular, cartilagineous, without external 



organs. ,\ large transversal narrow opening or mouth, liken cleft. Inside hol- 

 low, sides covered with undulated, plicated and lobed appendages .— This cuiious 

 genus belongs to the order JHonostemia, family Uymnotremia, and sub-family . /«/'»• 

 opia, next to Mei*aHoma ttucottwn,£fc. The nami means large cleft. 



7>S Megalisma maciiluta early spherical, smooth, 'brown with black spots — 

 I: .»;is taken on the hank of Newfoundland ; diameter six inches. Moving, roll« 

 ing on itself, coniractihle mouth shut or gaping • 



79. .Wil/'-['ijni<r:ioni:f 'mi-;. Elongate, ■ urved shnple, torulose or beaded ; seg- 

 ments unequal, oval in- oblong, roundeu, solid ; pores nearly in transverse rows, 

 subequal, suboval an! rath. t approximate — Fossil, near Lexington. One among 

 the three hundred N. sp. of fossil animals, discovered in Kentucky by .Mr. Clifford 

 and myself. 



X CLASS POIIOSTOVII V.— I HE POROSTOMES. 



XX V G .•>.■ u hum. Hody flat, floating, gelatinous, evanescent, homogen- 

 ous, without organs, unequally triangular. — I have first proposed this last class of 

 ai imals, which have oii'. invisible pores instead of mouths This genus bel ,s 

 to Uie order Gi/mnexii. famih Jneiidiu, sub familv .Ifd'-psiu, next to Pteropsi t 



80 Scalei.inm Himu >i. Flat, level and thin, transparent, the three sides u .i|^l 

 andstiaight, a iglrs u arh acute. — In the Atlantic ocean: breadth six inches. 



HI ficalenium urululutum. Margin undulated, one side much smaller, sides 

 siig'ith c .iv'il outward, angli s obtuse ; colour liyaline, faintly coloured with yel- 

 lowish. — In the Atlantic ocean. 



VLXS i S. 

 I CLASS. ELTR<lGYMA.— THE ELTROGYNES. 



82 Villa denticuliita. Branches and petiols striated and pubescent, petiols sub- 

 equal, leaves reniform, acute, subtrilobe, denticulate, denticules very small and 

 callose, shining above, while tomentose beneath, nerves rufous ; flowers polyga- 

 mous — In the state of New-York. I presented three years agi to the Philosophi- 

 cal Society of N. York a memoir of the Vil e-> of that stale, couta:. ing ten S[)ecies, 

 where, f seven were new : this is one ot them 



83. Pntnut eunecUa Shrubby, branches straight, round, biangular, leaves cu 

 neate, obtuse, erenate, base entire, glaucous beneath ; umbels sessile commonly 

 qnadriflore, calix serrulate, rugose transversal!}' — On the mountains of Penn- 

 sylvania, probably a Cherry shrub, it rises two feet, branches dark purple, leaves 

 and flowers small, peduncles short, three to five Mowers together, while ; it blc-s- 

 ■oiiis in Mav. 



84 Pnmut triflora Arborescent, brandies crooked ami smooth, leaves sub- 

 sessile, oblong-lanceolate, acuminate, erenate, sub-obtuse; umbels sessilc.com- 

 moiily triflore, ealix acute, petals erose — A tree twenty feet high, probably a 

 Cherry tree In the mountains of Pennsylvania. Flowers numerous, white, 

 Smelling strongly of honey. 



85. RotaptuiUa. Stem procumbent, smooth and crooked, stipular thorns 

 Straight, petiols pubescent, fnliolcs S-5, shining above, pubescent and pale be. 

 neath, obovatc, oblong, serrate, base entire, flowers solitary, peduncle hispid, 

 stigmas tomentose, umbilicate, fruits smooth, globular, depressed, calix appendi. 

 culated. — A very small shrub, four tosix inches high, fruits rather large, saffron 

 colour. Ifniiml it at Button lick in the knob hills of Kentucky. I have sent to 

 Europe the Prodromus of a monogranby of America liosesjfii which thirty-three 

 species and twenty varieties are described, whueof one-half arc new. 



i 



