52 COLUMBAKITJM. 



to that of the genus Fusus ; margin of the shoulder slightly curved, 

 but there is no sinus, properly so-called. 



Tryon,' although including Columbarium amongst the Pleuko- 

 TOJirn^, remarks that he feels " pretty well satisfied " that he was 

 correct in placing the typical species of the genus in Fusus. It 

 may be remarked, however, that regarding Murex colus, Linn., 

 as the type of Fusus, the type of the present genus does not, 

 even conch ologically, resemble it very closely. 



The inclusion of this genus in the Pleukotomidje rests almost 

 exclusively on the character of the radula, which is distinctly 

 toxoglossate. The passage can be understood, conchologically, 

 if Ancistrosyrinx, Dall, be studied in that connection. If we 

 exclude Pleurotoma cedonulli, Reeve, which, as Professor Dall 

 shows,^ should be classed in the genus last mentioned, then the 

 living examples of Columbarium would appear to belong exclusively 

 to the seas of Australia and Japan. 



Tt/pe. — Pleurotoma spinicinda, E. von Martens. 



Columbarium acanthostephes, Tate (sp.). 



1888. Fusus acanthostephes, Tate, Traus. Eoy. Soc. South Aust. vol. x. 



p. 133, pi. vii. fig. 7. 



1889. Fusus acanthostephes, Dennant, id. vol. xi. p. 41. 



1893. Fusus acanthostephes, Tate aud Dennant, id. vol. xvii. pt. 1, p. 219. 

 1895. Fusus acanthostephes, Tate aud Dennant, id. vol. xix. pt. 1, p. 111. 



This is a very typical example of the genus. Its protoconch 

 (Plate III. Pigs. 6a-J) is composed of two smooth turns, the earlier 

 of which is bulbous and the later carinate medially. This carina- 

 tion in the brephic stage is developed to an abnormal extent, and 

 is even spinose, as in adult individuals. 



The spire is turreted ; the whorls, six in number, are " ex- 

 cessively angulated, and coronated at the keel with large erect 

 or radially extended, compressed, hollow spikes. Last and 

 penultimate whorls with three rounded serrated ridges on the 

 posterior slope, reduced to one on the middle whorls, and entirely 

 absent on the earlier ones. Base of last whorl very contracted 

 and precipitous, ornamented with four or five angular keels, the 



' Manual of Concbology, vol. yi. 1884, p. 175. 



- Bull. Museum Comp. Zool. Harvard, vol. xviii. 1889, p. 78. 



I 



