116 CERITHIID^. 



suspend themselves to mangrove roots, weeds, etc., by means of 

 glutinous filaments proceeding from under their closed operculum 

 (PL 19, fig. 6). 



Subgenus TYMPANOTONOS, Klein., 1753. 



Shell with angular, spinose whorls ; columella twisted, canal 

 short ; outer lip broadly sinuated anteriorly, and less distinctly so 

 posteriorly. Animal with fringed siphon. P. FUSCATUS, Linn. 



Subgenus PYRAZUS, Montfort, 1810. 



Whorls angular ; aperture w T ith a short anterior canal, prolonged 

 posteriorly ; outer lip thickened, expanded. Animal with fringed 

 siphon. P. EBENINUS, Brug. 



Subgenus PYRAZISINUS, Heilprin, 1886. 



Combining the general characters of Tympanotonus and Tere- 

 bralia, differing from the former in the non-canaliculate character 

 of the aperture, and from the latter in the possession of a deep sinus 

 in the labrum, which is effuse, thickened, and carried completely 

 over to the labium, so as to enclose a round siphonal aperture, as 

 seen in Terebralia. 



P. CAMPANULATUS, Heilprin (PI. 19, fig. 10). Tertiary, Florida. 



Subgenus TEREBRALIA. Swainson, 1840. 



Shell with exterior varices and corresponding interior teeth, 

 surface spirally channeled ; aperture channeled behind, with short 

 anterior canal ; lip curved, dilated in front and prolonged so as to 

 partially close the canal ; columella with strong plications corre- 

 sponding to the teeth on the interior of the outer wall (PI. 19, fig. 

 4). 



P. PALUSTRIS, Brug., occurs in great numbers in the salt marshes 

 of the Eastern Archipelago, and is assiduously collected by the 

 natives, who roast them and suck the contents of the shell through 

 an aperture made by breaking off the tip of the spire. 



The internal teeth do not approach the aperture, and are only 

 discovered by making a longitudinal section of the shell. They 

 have not been found in any of the related groups. 



The genus BROTIA, H. Adams, 1866, is founded onMelaniapago- 

 dula, Gould, a Burmese species resembling in general form Tere- 

 bralia Humboldti, Val. Adams says that it has a multispiral 

 operculum, and therefore places it under the above name in the 

 Cerithiidse. I agree with Dr. Brot that the species has so com- 



