TURRILITES. G7 



T. testa elongato-turritdf smistrorsd, cosfatd et tuberculatd ; anfractibm convexius cu/i^, 

 inferne costatis, superne hituherculatis ; costis tuberculisque numero (Bqualihus ; aperturd 

 ovali ; umbilico niinimo. 



Shell turreted, turned to the left, with a spiral angle of about 25°; whorls slightly 

 convex, separated by a moderately impressed suture, and ornamented on their lower half 

 by numerous straight, elevated ribs, which rise at their upper ends into round tubercles, 

 and then terminate abruptly at a smooth spiral band, which encircles the shell ; above are 

 two rows of tubercles, the upper of which are smaller, and concealed by the next whorl ; 

 ribs and tubercles equal in number ; aperture oval, higher than broad ; umbilicus very small. 



[The complicaied form of the septa in this species is represented in PI. XXVII, fig. 15.] 



In Dixon's ' Geology of Sussex,' a TurriUte is described under the name of T. tripli- 

 catus, J. Sow., which appears to be a variety of the above. [This specimen is figured in 

 PI. XXVII, fig. 15.] 



Found in the Chalk ^larl of Ventnor, Isle of Wight ; and in the Chalk with green 

 grains, at Chardstock. 



9. TuRRiLiTEs BiFRONS? D' Orb. Plate XXVII, figs. 6, 7. 



{T. testa turritd, elongatd, sinistrorsd ; anfractibiis conveximculis^sulcolongitudinaliter 

 ornatis ; transve?'si??i costatis ; costis curvatis, interruptis , biseriatis, anterioribis ad 

 suturam divisis. 



The specimens figured difier from the ordinary examples of T. costatus in the flatten- 

 ing of the whorls, occasioned by the shallow furrow which divides the curved transverse 

 ribs into a double series : the ribs are simple, rounded, and about as wide as the inter- 

 spaces ; the lower series of ribs is again divided by a furrow exactly at the suture, forming 

 a third set of little tubercles, only visible on the base of the shell when broken. 



Found in the Lower Chalk, of Ventnor.. Isle of Wight.] 



10. TuRRiLiTES WiESTii, SJiarpe. Plate XXVII, fig. 8, 9 a, b, and fig. 17. 



T. testa turritd^ sinistrorsd ; anfractibm externis rotundatis, tuberculatis, inius lavibus ; 

 tubercuUs conicis 4 serialibus, numero equalibus, superiore et inferiore nmioribus, in suturd 

 profujidd cremdatd, coalescentibus, mediis bitiis majoribus prominentibus ; aperturd sub- 

 quadratd; umbilico parvo. 



Shell tui'reted, tuberculated ; spine turned to the left, with a spiral angle of about 22°; 

 whorls rounded, separated by a deep, crenulated suture, ornamented with four rows of 

 conical tubercles, which are of the same number in each row, and set obliquely under one 



