18 TROCHUS. 



Vae. maximus Koch. PI. 1, fig. 9. 



Shell less ponderous than T. niloticus ; form strictly conical ; 

 whorls of the spire decidedly plicate or tuberculate, planulate ; 

 body- whorl not dilated at the periphery ; base flat, concentrically 

 grooved ; columella less oblique than in the type. Alt. 95, diam. 

 95 mill. India 0. ; Cochin- China ; Viti Is. 



T. maximus Koch, in Philippi, Ahhild. u. Beschreib., Trochus, t. 

 iv, f. 3. 1844. — T. marmoratus Kiener, Sj). et Icon., t. 11. — T. nilo- 

 ticus Rve., Conch. Icon., f. 3. 



T. maximus is an arrested or primitive form of niloticus. In the 

 conic form, flat, lirate base, and sculptured spire, it exactly resembles 

 an immature specimen of the latter species ; but at the same time, it 

 retains these characters in adult individuals. I do not know whether 

 both occur in the same locality ; if they do, I would incline to consider 

 them distinct. The finest suite I have seen of the T. maximus is from 

 the Viti Is., collected by the late Andrew Garrett. 



Since the above was written I have seen a discussion of these two 

 forms by Dr. von Martens (Ann. and Mag. N. H., 1869, p. 97.) 

 T. maximus is considei-ed distinct from niloticus, and the differences 

 indicated by this distinguished zoologist. 



T. ACUTANGUEUS Chemnitz. PI. 2, fig, 10. 



Shell conic-pyramidal, axis imperforate but appearing sub-umbili- 

 cate, solid, thick, white, longitudinally flammulate with bright red ; 

 spire conic, apex acute, whorls 10, spirally encircled by numerous 

 (about 10 on upper surface) beaded lira^, which are separated by 

 superficial interstices ; above the sutures there is a series of short 

 folds or knobs which usually become obsolescent upon the periphery 

 of last whorl ; body-whorl obtuse at the periphery, nearly flat below, 

 indented around the false umbilicus, obsoletely concentrically lirate, 

 the lirse about 9 in number, red and white articulated, interstices 

 white ; aperture transversely rhomboidal, somewhat I'cnuided ; colu- 

 mella nearly vertically descending, subdentate at base, above with 

 a profoundly entering spiral fold; parietal wall bearing a heavy 

 transparent callus, which is excavated around the axis. 



Alt. 55-70, diam. 45-60 mill. 



East Indies ; Philippines ; N. Australia. 



Trochus acutangulus Chemnitz, Conch. Cab., v, p. 81, t. 167, f. 

 1710. 1781.— T. conus Gmel., Syst. Nat., xiii, p. 3569. (1788)— T. 

 elatas Lam., An. sans Vert., vii, p. 21. 1822. — T. alius Perry, Con- 

 chology, t. 47, f 3, (1811)— T. turris Phil. Zeitsch.f. Mai, 1846, p. 



