SOLARIUM. 235 



Area media crebre rugosa, prnpe umbilicum fusco minute macu- 

 la! a, turn carina parva monilii'cra alba cincta. Umbilici margo 

 nodulis magnis fuscis ornata. Obs. The most distinguishing 

 features of this beautiful shell are the brown-reddish flashes of 

 colour, in which it resembles S. fuliginomm, and the rounded 

 lenticular base, in which it differs from all species of the Architec- 

 ionica section." Possibly an abnormal form of 17. 



19. discus (f. 57, 5S), Philippi. — " T. depresso-conica, lenticu- 

 laris, acutangula, anfractibus supra planulatis, cingulis tribus 

 moniliformibus valde depressis subobsoletis ornatis ; basi linea 

 parum elevata marginem cingente, aliaque impressa, umbilicum 

 mediocrem valde crenatum cingeute, sculpta." Obs. Unknown to 

 me. Philippi adds that the colourless specimen sent him by 

 Scacchi,in tolerable condition, exhibited two scarcely raised threads 

 between the belts; that its keel, although acute and very de- 

 pressed, was rounded off at the angle ; that its convex base (a 

 little concave, however, before the extreme margin), rayed with 

 dichotomous folds, a continuation of the umbilical teeth, was 

 otherwise smooth (the specified sculpture excepted) ; that its um- 

 bilical ridge projected considerably inwards ; and that its mouth 

 was very depressed, and very sharply angulated at the outer lip. 



20. placentula (f. 23, 24), Hinds.— T. discoidea, fulva; cin- 

 gulum marginale rufo maculatum, carinam unicam latam obtusam 

 pervalidam, valde eminentem, denique formans. Anfractus pauci, 

 vix convexi, cingulo granoso latiusculo alium simile perparvum, 

 quod labrum versus evanescit, sequente, inferne instructi; striis 

 paucis distantibus etiamque cincti : anf. apicales juxta suturam 

 perangustam nonnunquam plicato-corrugati. Basis juxta cari- 

 nam concaviuscula et filis 2—3 tenuissimis circumcincta; sequi- 

 tur deinde hlutn vix granosum, striolasque paucre spirales; umbi- 

 licum versus satis amplum pallidum multidentatum, convexa vel 

 tumida, et denique rugis radiantibus crassis plicata, sulcoque 

 unico nonnunquam cincta. O/js. Remarkable for the absence of 

 secondary keels, and of an infrasutural sulcus. 



21. pseudo-perspectivum (f. 83, 84), Brocchi. — T. depresso- 

 conoidea, supra luteo-fulva, infra albida ; nisi fortasse ad carinam 

 latam, declivem, peracutamque, immaculata : sutura subcanalicu- 

 lata. Anfractus superne rotundati, et nisi juxta apicem spiral 

 depressum, ubi sulcis arcuatis radiati sunt, lseves; pars (circiter) 

 tcrtia inferior sulcis duobus, cingulisque duobus, quorum supe- 

 rius est angustius, ornata ; cingula apicem versus crenulata, 



