172 Memoirs of the Indian Museum. [Vol. VII, 



ally been named Dolium ormarense, and which, as shown by the characters of its 

 aperture, undoubtedly belongs to the same group as Dolium tessellatum. The size, 

 number, and spacing of the primary ribs on the body-whorl is in complete agreement 

 with the recent form from which the fossil differs owing to the presence of a well- 

 developed intercalary rib of the second order in each interval at all stages of growth ; 

 the broader posterior primary intervals also showing indications of threads of a third 

 order. The spire is more sunken than in the recent form and recalls that of Dolium, 

 maculatum. 



In his first monograph on the tertiary fossils of Java (Tertiärschichten auf Java, 

 p. 40, 1879) Martin has mentioned the occasional presence of intercalary ribs on the 

 body-whorl of " Dolium costatum," that is therefore of D. tessellatum. On the 

 strength of this observation, Boettger (Die T ertiaer formation von Sumatra, und ihre 

 Thierreste, 2nd part, p. 84, pi. vi, figs. 4, 5 ; Palaeontographica, Supplementary 

 Vol. Ill) has referred to Dolium costatum as a variety martini, a tertiary fossil from 

 Sumatra in which intercalary ribs are conspicuously developed at all stages of growth. 

 Nevertheless, since Martin specially mentioned that the occasional development of 

 intercalary ribs takes place on the body-whorl, the remark doubtless applies to the 

 adult character of full-grown specimens ; especially as, in his latest work on the 

 subject (Samml. des geol. Reichs- Museums in Leiden, new series, Vol. I, 1899, p. 161 )> 

 Martin has specially described the complete or almost complete disappearance of the 

 interstitial decoration, with increasing growth, on the spire- whorls. In this latest 

 work, Martin has accepted Boettger's identification without discussion, by simply 

 recording it in the synonymy. Yet the intercalary ribs, in the specimens figured by 

 Boettger, are far more prominent than is known ever to be the case in specimens of 

 Dolium tessellatum of corresponding size. There is every reason to believe that the 

 fossil Dolium martini is identical with the form provisionally named Dolium orma- 

 rense, especially as the spire seems to agree exactly with that of the Mekran fossil 

 and not with the true Dolium tessellatum. 



Another doubtful form is Dolium inodjokasriense, Martin, fossil from the later 

 tertiary of Java (Samml. des geol. Reichs- Museums in Leiden, new series, Vol. I, 

 p. 160, pi. xxv, fig. 370), in which the spire is disposed exactly in the same manner 

 as in Dolium maculatum, with exactly the same spiral decoration consisting of con- 

 spicuous ribs or threads of three orders, with indications of a fourth, this decoration 

 being similarly continued on the corresponding posterior portion of the body-whorl. 

 Anteriorly to the level of the suture, the body-whorl is said to differ from that of 

 Dolium maculatum owing to the presence of only two alternating orders of spiral 

 ornaments instead of three ; only, this part of the solitary available specimen is so 

 poorly preserved as to permit of a doubt as to whether the ribs interpreted as 

 representing the first order may not partly correspond with the expanded ribs of the 

 second order as frequently observed on adult specimens of Dolium maculatum, in 

 which case the fossil under consideration would be a specimen of D. maculatum such 

 as is already known in a fossil condition from the upper tertiary of the Mekran. 

 Otherwise, if the interpretation accepted in the original description be correct, the 



