342 M. o. A. L. morch's review of the vermetid^. [Nov. 12, 



pone varices infiati ; unfr. ultimus solutus suberechts, peritre- 

 mate infiexo, postice rotnndato-lohato, inde apertura coarctata 

 reniformi. 

 Long, axis circ. 8 m. ; diam. anfr. ult. Ig m. 

 Hab. Ins. St. Croix, on Isognomon alatum, Gm., from the roots of 

 the RMzophora mangle, L. {Oersted); about 5 specimens. I have 

 seen this form principally on the impressed linear varices and smooth 

 surface of the first whorls of a specimen of the following form ; the 

 constricted aperture must then, of consequence, become dissolved 

 with age. 



Var. ft. (Thylacodus). 



T. pallide ferruginea vel albescens, lateraliter affixa, spiraliter 

 torta ; anfr. contigui tenuiusculi, liris longitudinalibus et rugis 

 transversis reticulati ; columella lira mediana et interdum 

 utrinque lirula obsoleta remota ; anfr. idtimus solutus, longus, 

 tortus, pallidus, Iceviuscidus ; anfr.primi ut prcecedentes ; spe- 

 cimen vidi cujus anfr. primi planorbiformes. 



Sab. St. Croix, cum prsecedente {Oersted). 



Var. y. (Vermetus). 



T. cylindrica lateraliter affixa spiralis, anfractibus contiguis, 

 sutura dilatata applanata pallida; columella lira mediana 

 distinctissitna, utrinque lirula obsoleta, in anfr. medianis {la- 

 teris affixi) laminis duabus latis, oppositis, hyalinis, lacteis, con- 

 vexiusculis, margines fere attingentibus. 

 Axis long. 27 m., diam. aperturse 3 m. 

 Hab. cum prsecedentibus. 



The ten or twelve first whorls do not show any laminae inside. In 

 the thirteenth whorl is a pair of rudimental laminae (perhaps broken 

 off) ; in the two following whorls the laminae are very broad, leaving 

 a narrow slit between them, and dividing the interior into two unequal 

 ])arts, of which the interior is about a third part. In the sixteenth 

 whorl the laminae are very short, leaving a large gap between 

 them, and decreasing to a feeble Una in the seventeenth and two 

 following. 



*0' 



Var. h. GORDiALis (Vermetus). 



T. differt a prcecedente anfractibus longissiniis, irregulariter 

 spiraliter tortis, glomeratis, foveolato-reticidatis ; cohunella 

 liris tribus cequidistantibus subcBqualibus, lirulis obsoletis in- 

 tercalantibus ; lamince internee %it prcecedentis. 



Diam. apert. 4 m. 



Tubulus marinus vermicularis, concameratus, striatus, notis nigris 

 pwictatus, lucidus, ex fusco rufescens, Gualt. t. 10. f. Z. 



Serpula decussata. Lam. v. p. 363.no. 7; ed. 2. v. p. 620 (nonGm.). 



Vermetus decussatus, Blv. Dict.Sc. 1827,t.xlviii.p.555(A>?;/;M/rt). 



Vermetus decussatus, Desh., Lam. ix. p. 65. no. 2. 



Vermicularia glomeraia, Gravenh. Tergest. p. 59. var. 2 a (ex 

 specira. orig. ?). 



