38 NOETLING: MARINE FOSSILS FROM MIOCENE, UPPER BURMA. 



slopes and is slightly excavated ; the keel is set with short, pointed 

 tubercules, from which issue strong longitudinal ribs, which disappear 

 in about half the height of the whorl ; it must be noted that these ribs 

 are only well seen on young specimens, while on larger ones they 

 are very short and indistinct. As each whorl is enveloped by the 

 succeeding one up to the keel, the spire appears slightly spinose. 

 On young specimens there exist also fine revolving ribs which be- 

 come stronger towards the base ; on full-grown specimens the revolv- 

 ing ribs disappear on the upper part, where they are replaced by 

 irregular lines, and only remain near the base. Aperture high and 

 narrow ; outer lip straight and thick, probably denticulated inside. 

 Inner lip callous ; five strong plaits on the columella. 

 Locality.— Common at Minbu and Yenangyat. 

 Remarks. — The sculpture of this species varies a little during 

 the time of growth, inasmuch as it is more distinctly marked on 

 younger specimens than on full-grown ones, on which it nearly disap- 

 pears ; the difference is so marked that at first sight one might be led 

 to believe that the younger form represents a different species, but 

 on laying bare the earlier whorls of a full-grown specimen I could see 

 that the longitudinal and revolving ribs gradually grow more distinct. 

 It is for this reason that I have united Voluta cythara, d'Arch., with 

 Voluta dentata. Sow.; in fact young specimens of this species cannot 

 be distinguished from Voluta cythara, d'Arch. 



I consider the chief distinguishing features of this species the line 

 of tubercles on the keel, from which issue moderately long longitudi- 

 nal ribs. 



OLIVA DJOCDJOCARTVE, K. Martin, Plate IX, Fig. i— ic. 



1883 — 87. Oliva djocdjocartse, K. Martin, Beitrage zur Geologie Ost-Asiens und Austra- 



liens, vol. Ill, page 77, plate V, fig. 80. 



The shell is oblong, subcylindrical, and has a low spire, of at 

 least six low, flat whorls, divided by a deep, canal-like suture, other- 

 wise they are perfectly smooth ; the last whorl is, except for some 

 striae of growth, smooth ; the aperture is narrow and straight ; outer 

 lip thick ; on the columella five larger plaits, between which small 



( 38 ) 



