26 ODONTOSTOMIN^E. 



no large vessels, coarse reticulation being confined to the two ends 

 of the lung, (fine transverse venation of the intermediate space being 

 omitted in the figure). In Macrodontes (pi. 15, fig. 29), the lung is 

 short, a modification correlated with the reduced number of whorls 

 of the shell. There is a strong secondary pulmonary vein, and a 

 small tertiary, the cardiac side of the lung having a strong, branch- 

 ing venation, while on the intestinal side the venation is fine, close 

 and mainly transverse. The pattern of lung venation in Macro- 

 dontes is unusual, and I have seen nothing like it elsewhere; in the 

 Bvlimulidce. It reminds me of Strophocheilus and the Acavidce. 



The genitalia are exceedingly lengthened in Odontostomus and 

 Anostoma, much less so in Macrodontes. There are no accessories, 

 the whole apparatus being Bulimuline. 



Shell. The heliciform groups of BulimuKnce, such as Piatybostryx 

 and Oxychona, prepare us for shortened shell-contours in the Odnnt- 

 ostomiiKe, In Tomigerus the modification is not great ; but Anos- 

 toma presents a form so bizarre that in the total absence of informa- 

 tion upon its life history, no useful theory can be formulated to 

 account for its peculiarities. 



The apical sculpture in OdontostominnR varies within the same wide 

 limits observed in Bulimulincz, and presents nearly identical patterns. 

 In Anostotna, Tomigerus and Anctns the apex is smooth, as in the 

 Bostryx type of BulimuUnee. In Macrodontes (pi. la, fig. ol>) it is 

 spirally lirate. In Odontostomus, including the sections Mrl<-a.ndia, 

 Bahiensis (pi. 15, f. 31) and Cyclodontina, it is like that of Dry- 

 tiuzus. In ffyperaulax and 0. (Plagiodontes) dentatua (pi. 15, f. 25) 

 the apex has waved wrinkles as in typical Bnlimulns, while in 

 Spixia (pi. 15, fig. 34) and the other species of Plagiodontes (pi. 15, 

 fig. 32) there are straight riblets like those of Orthotontium, Ncesiotus. 

 etc. There is an incomplete transition from the Drynuzns type to 

 the Spixia type by the growing predominance of vertical, with 

 gradual loss of spiral sculpture, exemplified in some species. 



The teeth obstructing the apertures of the Odontostonrina are far 

 more stable in position and arrangement than would be thought on 

 first inspection. They may most readily be described by use of the 

 terminology of the similar teeth of Pupidtz. 



Lamellce on the parietal wall : Angular, parietal and infraparietal 

 lamella;. 



Lamella on the coluin<>ll<tr margin: Supracolumellar, 

 and sub-columellar lamella; ; basal fold. 



