﻿DUMORTIERIA PSEUDORADIOSA. 247 



the specimen depicted in PI. XLT, fig. 1, the inner whorls must have been very 

 much stouter than any specimeus of Bum. radians ; and in figs. 9, 10, of the same 

 plate is shown what is most probably a fragment of the inner whorls. The com- 

 parison with Bum. radians is made more difficult because figs. 9, 10, PI. LXI, are 

 the only example of the young Bum. pseudoradiosa that I can give ; but the 

 thicker and broader whorls, and the more depressed, slightly narrower umbilicus 

 are the points to be relied upon. 



Between the adult Bum. 'pseudoradiosa and adult Bum. striatulo-costata, PI. XL, 

 figs. 1, 2, there is apparently great similarity. The whorls of the latter, however, 

 are distinctly narrower ventrally ; and the ventral area is more acute, more sloped, 

 and consequently not so well defined. The sides of the whorls also slope towards 

 the ventral area, instead of being almost parallel as in Bum. pseudoradiosa. How- 

 ever, the great distinction is the coarse ribs in the inner whorls of Bam. striatulo- 

 costata ; and this introduces the young of the two species, when the differences are 

 shown to be more accentuated. A comparison of similar-sized young specimens, 

 PI. XL, figs. 5, 6, and PI. XLI, figs. 0, 10, will be sufficient to show this without 

 any comments of mine. 



Of the derivation of this species I do not feel certain. It seems to be too 

 thick in the inner whorls to have come from Bum. Levesquel, but it certainly has 

 originated from some coarser-ribbed species. 



The grand specimen which forms the subject of PI. XLI, figs. 1, 2, is to the 

 best of my knowledge the finest British representative of this species. I have 

 known the specimen for the last ten years, and it has had a rather eventful 

 history. Formerly in the collection of my friend Mr. T. C. Maggs, F.G.S., it was 

 borrowed by my father to illustrate his paper on " Terminations of Ammonites," 

 and its mouth was depicted. Some years afterwards it passed, with the rest of 

 Mr. Maggs' collection, to Mr. Damon, of Weymouth. Being broken, it was put 

 aside with the fragmentary and inferior specimens ; but after considerable search 

 I fortunately rescued it from such company during my visit to that town, and it 

 now forms one of the treasures of my collection. 



The Yeovil Sands of Yeovil Junction 1 and Bradford Abbas, Dorset, have 

 yielded the figured examples of this species. The Bumortieria-heds (Jurense-zone), 

 the middle of the so-called " Cotteswold Cephalopoda-bed," have afforded some 

 poor specimens at Wotton-under-Edge, and Penn Wood, near Stroud, Gloucester- 

 shire. 



PI. XLI, figs. 1, 2, give two views of a fine example possessing the mouth - 



1 The locality "Yeovil Junction" has been applied somewhat loosely. Yeovil Junction is in the 

 county of Dorset, and many specimens have been obtained from the sandy, calcareous beds in the 

 sands behind the station. Other specimens have been obtained from a quarry in the sands about a 

 quarter of a mile distant ; but this quarry is in the county of Somerset. 



