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



4. Trophon acanthodes, 1 Watson (PI. X. fig. 6). 



Trophon acanthodes, Watson, Prelim. Report, pt. 14, Journ. Linn. Soc. Lond., vol. xvi. p. 386. 



Station 308. January 5, 1876. Lat. 50° 8' 30" S., long. 74° 41' W. W.Patagonia. 

 175 fathoms. Blue mud. 



Station 311. January 11, 1876. Lat. 52° 45' 30" EL, long. 73" 46' W. Western 

 Patagonia. 245 fathoms. Blue mud. Bottom temperature 46°. 



Shell. — Strongish, chalkily porcellanous, yellowish, fusiform, with a high scalar spire, 

 small apex, sharply keeled and radiatingly spiked whorls, a rounded contracted base, and 

 a long, narrow, but strong snout. Sculpture : Longitudinals — the surface is scored with 

 close, very irregular lines, formed by the slightly raised edges of thin imbricated procum- 

 bent lamellae, between which there are almost microscopic scratches in the lines of 

 growth ; there are 8 or 9 feeble oblique riblets on the lower part of the whorls, these die 

 out on the base. Spirals — toward the upper part of each whorl there is an acute 

 angulation with an expressed rounded keel, from which projects a coronal of longish rays, 

 or pointed, upturned, retroA'erted vaulted spikes, each of which forms the origin of one of 

 the longitudinal riblets ; below this keel there are feeble, irregular, rounded threads, which 

 may be recognised on the snout. The whole surface is covered with very fine, close- 

 set, rounded threadlets. Colour yellowish, with a singularly harsh surface. Spire high, 

 scalar. Apex mamillate, but small, consisting of nearly three smooth, cylindrical, 

 embryonic whorls, of which the extreme tip is slightly immersed. Whorls 7 to 8 in all, flat 

 above, sharply angulated, keeled and coronated, conically contracted to the lower suture ; 

 they are all small, but the last, which is a little tumid, with a rounded base, Very much 

 contracted and produced into a long, straight, spike-like snout. Suture sharp and deep, 

 in the bottom of the broad depression between the keels. Mouth club-shaped, being 

 rather small and oval above, and contracted below into the long, narrow, but patulous 

 canal. Outer lip roundly arched, angulated at the keel, where the vaulted spikes 

 present a canal ; it is patulous below and down the whole anterior canal. Inner 

 lip rounded above, where it expands on the body, joining the outer lip without any 

 angulation ; at the top of the canal it projects in a slight blunt tooth ; from this 

 point it becomes much narrower, and only the excessively narrow edge of the glaze 

 can be recognised, almost hiding behind the long straight pillar. H. 1*5 in. B. (exclusive 

 of the spines) 0"64. Penultimate whorl, height - 22. Mouth, height, 1, breadth 

 0-32. 



This species resembles Trophon vaginatus, Jan, but is much more tumid on the base, is more 

 constricted at the anterior canal, has a straighter snout, a less contracted suture, and a lower 

 spire. 



1 dxatSuidri;, prickly. 



