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BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



which its more broadly expanded peristome and the exceedingly feeble 

 color banding will distinguish it. 



The type (U.S.N.M. No. 355452) has 186 axial ribs on the last turn. 

 It has almost 4 whorls remaining and measures: Length, 10.3 mm.; 

 greater diameter, 5.7 mm. ; lesser diameter, 4.8 mm. 



Three topotypes (U.S.N.M. No. 180680) yield the following meas- 

 urements : 



OPISTHOSIPHON (OPISTHOSIPHONA) SIMPSONI ABACOENSIS, new subspecies 



Plate 36, Figure 4 



This subspecies was collected by Owen Bryant at Matthew Point on 

 the south-central coast of Great Abaco Island. It is readily distinguished 

 from the other races of simpsoni by its deeply channeled suture. It is 

 nearest related to Opisthosiphon (Opisthosiphona) simpsoni saccharinus, 

 as far as the more distant spacing of the axial ribs is concerned, but 

 differs from this also in having the inner lip of the outer peristome 

 much less expanded. 



The type (U.S.N.M. No. 355451 has 138 axial ribs on the last whorl 

 and has a little more than 3 whorls remaining. These measure: Length, 

 10.7 mm.; great diameter, 6.5 mm.; lesser diameter, 5.1 mm. 



Three topotypes (U.S.N.M. No. 180686) yield the following meas- 

 urements : 



OPISTHOSIPHON (OPISTHOSIPHONA) SIMPSONI SACCHAKINUS, new subspecies 



Plate 36, Figure 11 



This subspecies was collected by Owen Bryant on Sugar Loaf Cay 

 of! the north central coast of Great Abaco Island. It is nearest related 

 to Opisthosiphon (Opisthosiphona) simpsoni simpsoni, from which it 

 differs in being more slender, in having fewer ribs, and in lacking the 

 conspicuous banding. 



The type (U.S.N.M. No. 355450) has 134 axial ribs on the last whorl, 



