

MOLI/CSCA. 39 



6. Pleirrotoma (Glyphostoma) spurca. (Plate IV. figs. F-F 1 . ) 



Clavatula spurca. Hinds, Voy. ' Sulphur; p. 17, pi. 5. fig. 14; Reeve, 



Conch. Icon. fig. oil*. 

 Pleurotoma ravi ("»" Hinds), Conch. Icon. fig. 250. 



Hah. Port Molle, Arafura Sea, N. Australia, 32-36 fms., and 

 Port Darwin, N/W. Australia ( Coj>f>rng< r). 



This interesting species is subject to considerable variation both 

 in form and sculpture, but is nevertheless generally very easily 

 recognized by the transverse plaits on the columella and the large 

 deep and laterally directed sinus near the upper end of the much 

 thickened labrum, which is aimed within with five or six denticles 

 or short lira* not reaching the crenulated edge. The basal canal is 

 contracted and a little recurved. The type has ten costa) upon the 

 last whorl, but this number is sometimes exceeded by two more. 

 The principal lira? are normally two in number upon the upper 

 volutions, one being at the middle, the other below, nodulous upon 

 the costas. Above these, occupying the upper part of the whorls, 

 are a few uninterrupted thread-like lira?, about four upon the 

 penultimate and antepenultimate whorls. The body-whorl has 

 about fifteen principal spiral lira?, two of which pass above the 

 extremity of the outer lip. Some varieties have three or even four 

 subequal principal lira? on the lower half of the upper whorls, and 

 twenty to twenty-four upon the last, but all agree in having the 

 finer lines above, which also at times exceed the typical number. 

 The largest specimen considerably exceeds the dimensions of Hinds s 

 type. It is 1 8 millim. in length and in width, measuring above 

 the aperture, which is 8 long. Another smaller example is re- 

 markable for the shortness of the mouth : it is 1 2 long, 4 broad, 

 with an aperture 4| iu length. 



7. Pleurotoma ( ?) gracilenta, var. 



Pleurotoma gracilenta, Reeve, Conch. Icon. fig. 114. 

 Var. = PI. contracta, Reeve, I. c. fig. 116. 

 Var.=Pl. fusoides, Reeve, I. c. fig. 349. 



Hah. Arafura Sea, X. Australia, 32-36 fms. ; bottom — sand, mud, 

 and shells (Coppinger); Philippine Islands (Cuming). 



This species does not conveniently fall into any of the recognized 

 groups of Pleurotoniida?. In form it resembles - some species of 

 Daphnella, but has not the minutely reticulated nuclear whorls of 

 that section, and the labral notch is hardly at, but a trifle below, the 

 suture. I fail to perceive any sufficient characters to separate 

 specifically the three so-called species described by Pieeve ; indeed 

 PI. contracta and PI. fusoides are all but identical. The type of 

 P. gracilenta is a trifle more attenuated than the other two, but 

 scarcely differs in any other respect. All are longitudinally eostate 

 and spirally Urate, the costae numbering about twelve on a whorl, 

 attenuated above at the suture, and becoming obsolete upon the 

 bodv-volution towards the narrowed anterior end ; the principal 



