582 THE VOYAGE OF H.M.S. CHALLENGER. 



Adanson's whole description of " Lt Fossar " (loc. cit. supra) is admirable ; his figure is equally 

 so. Adams in his Genera (vol. iii. pi. xxxiii. fig. 7) gives a figure (copied from Philippi, Conch. 

 Cab., loc. cit. supra) in which he misrepresents the frontal lobes entirely. 



2. Fossa?-us cereus, Watson (PI. XLIII. fig. 4). 



Fossarus cereus, Watson, Prelim. Report, pt. 5, Journ. Linn. Soc. Lond., voL xv. p. 97. 



Station 184. August 29, 1874. Lat. 12° 8' S., long. 145° 10' E. East of Cape 

 York, North-east Australia. 1400 fathoms. Globigerina ooze. Bottom temperature, 

 36° Fahr. 



Animal (PL XLIII. fig. 4d) differs from Fossarus ambiguus, Liune, in the absence 

 of the eyes, of which I could discern no trace, and in the want of the frontal lobes at the 

 base of the tentacles ; the muzzle seemed to be slightly bifid. In the dried-up condition 

 of the specimen this, with the operculum, was all I could make out. 



Shell. — Globosely conical, not thin, but waxily translucent, with a thin polished yellow 

 epidermis. Sculpture: there are many oblique, fine, rather obsolete lines of growth. 

 Spirals — there are several irregular, unequally parted, rounded and rather obsolete spiral 

 threads, which are closer on the base. Colour : that of the shell is a translucent white ; 

 it is covered with a very thin, most persistent, hard, smooth, and horny epidermis. Spire 

 somewhat scalar. Apex eroded. Whorls three (remaining), convex, but a little com- 

 pressed towards the middle, round on the base, of very rapid increase, the mouth being fully 

 two-thirds of the whole length. Suture deep and irregular, but not canaliculated, except 

 where eroded. Mouth oval, bluntly pointed above, glossy within. Outer lip thin and 

 sharp, with a very regular curve, prominent on the base, and a little patulous towards the 

 point of the pillar, where it is slightly, openly, and a little obliquely canaliculate. Pillar 

 rather short, hollowed above, bending over a little to the left, and terminating in a slight 

 oblique tooth, which results from the slight canaliculation in which the mouth terminates, 

 and which, as in Rissoina, is hollowed out of the point of the pillar. Inner lip por- 

 cellanous white, slightly reverted, and very closely appressed ; a very thin glassy layer 

 across the body unites the lips. Umbilicus none. Operculum, thin, cartilaginous, yellow, 

 semilunar, subspiral. H. 0*2 in. B. 0'\§, least 0*15. Penultimate whorl, height 0'065. 

 Mouth, height 0-17, breadth 0"1. 



The generic place of this shell cannot be considered as satisfactorily determined. The whole 

 aspect removes it from Admete and even more from Rissoina, which presents in a stronger form the 

 basal sinus. The absence of an umbilicus removes it from Isapis, of which the Isapis fenestrata, 

 Carp., has a swelling on the pillar lip, strongly suggestive of this Australian species. On the whole, 

 the general appearance of the shell is liker that of a Fossarus than anything else ; and though 



