MOLLUSCA. HEDLFY. 69 



displacement of the columella plaits distinguish Altivo.su m . 

 Judging from literature, V. ciqiitcUimi, Liune, makes the 

 nearest approach to the new genus, but I have no specimens to 

 decide if it should be included, or not. 



'Chascax', referred by its author to the Muricida?. has a strong, 

 if apparently superficial resemblance to Alticasinn. Though its 

 author denied 1 to it any columella plaits, Tryon 2 has affirmed 

 their existence. Several years ago Mr. J. Dennaut showed me 

 an undescribed Victorian Tertiary shell which from my re- 

 collection might belong to this genus. 



The type species, Latirns aiirantiacus, was described from a 

 young shell 46 mm. long, dredged alive by Dr. Verco in 

 Backstairs Passage, S.A. Afterwards he dredged in St. Vincent 

 Gulf two others, one of which had lost four or five whorls and 

 had four remaining in a length of 57 mm. This was taken 

 alive. The other was a very worn example of an older shell, and 

 had about four whorls remaining in a length of 88mm. 

 Dr. Verco kindly lent these to me for comparison with 

 "Endeavour" material. 



Between that here figured and the one illustrated by 

 Dr. Verco, great difference appears. That is partly due to the 

 difference between youth and age, a difference here unusually 

 great. But the "Endeavour" shells are beset with prominent 

 spines which are absent from the eastern shells. The South 

 Australian specimens agree in having fewer and bolder ribs 

 than those from West Australia, so that it is difficult to decide 

 Avhether here are one or two species. I prefer to take the con- 

 servative view that the differential characters are probably 

 variable and that a fuller series will unite these extremes. 



The " Eudeavoiir " series are therefore described under the 

 name of . 



AljTIVASUM AUKANT1ACUM, VerCO, up, 



(Plate ix., tig. 2.) 



Latirus aurantiac'us, Verco, Trans. Roy. Soc. S. Austr., xix., 

 1895, pp. 89, 107, pi. ii., figs. 1, la. Id., Melvill, Jourii. of 

 Conch., xiii., 1911, p. 167. Xot Latirus atir.nt!'irii*, Montfort, 

 Conch. Syst., ii., 1810, p. 531. 



Shell large, for its size rather light and thin, ovate-acuminate, 

 broadly and deeply perforate. Colour uniform salmon red. 

 Whorls eleven, gradate, slowly increasing, angled at the suture. 



1 Watson Proc. ZooL Soc., 1873, p. 361, pi. 36, fig. 30. 



2 Tryon Man. Couch., iii., 1881, p. 89. 



