DENTALIUM-FUSTIARIA. 127 



oblique encircling wrinkles (sometimes indistinct from superficial 

 erosion), obsolete toward the aperture where there are fine growth 

 striiB only ; no longitudinal sculpture. Aperture very oblique, oval, 

 wider than long ; the peristome thin and fragile. Anal orifice cir- 

 cular and simple. 



Length 11, antero-posterior diam. of aperture I'l, right to left 

 diam. 1*25 mill. 



Port Stephens, New South Wales, Australia (John Brazier). 



Allied to D. presstim and D. hrevicornu Pils. & Sharp. It is 

 smaller and less compressed on the inner curve than the former, with 

 no trace of longitudinal sculpture and more oblique growth strise. 



Subgenus Fustiaria Stoliczka, 1868. 



Fustiaria Stol., Mem. Geol. Surv. India, Cretaceous Fauna of 

 Southern India, ii, p. 439 ; types D. eburnenm Lam. and circinatum 

 Sowb. (1868). — Pseudantal'is Monterosato, Nomencl. Gen. e. Spec. 

 Conch. Medit., p. 32, for fissura Lam., inversum Dh., rubescens Dh., 

 tenuifissa Monts. and filum Sby. (1884). 



Shell regularly tapering, arcuate, polished ; either smooth or 

 sculptured with regular encircling grooves, dividing the surface of 

 the tube into short oblique segments. Aperture circular. Anal 

 orifice round or ovate. Slit a very long, straight, linear cleft on the 

 convex side. Type D. circinatum Sowb. 



Soft anatomy unknown. Species Eocene to recent. 



Some recent authors have treated this group as of generic value; 

 but unless we dismember Dentalium and recognize a dozen or more 

 genera in its stead, we are obliged to rank Fustiaria as a subgenus. 

 The more conservative course has been chosen because the anatom- 

 ical characters of Scaphopods are still but little known ; the study 

 of the class is in its infancy. Those who come after, when scalpel 

 and microtome have given their testimony, will be better able to 

 decide upon the true generic groups of the Scaphopoda, than we are 

 now, when the soft anatomy of but a handful of species belonging 

 to two or three of the groups has been worked out. 



But one or two living species of Fustiaria are known ; but there 

 are numerous Tertiai-y forms, and perhaps some from the Cretace- 

 ous. 



I. Shell annulated, D. politum. 



II. Shell smooth, D. stenoschizum, D. tenuifissmn. 



