1884.] MR. W. R. O. GRANT ON SICYDIUM AND LENTIPES. 153 



1. A Revision of the Fishes of the Genera Sicyd'mm and 

 Lentipes, with Descriptions of five new Species. By 

 W. R. Ogilvie - Grant. (Communicated by Dr. 

 GiJNTHER, F.R.S., V.P.Z.S.) 



[Eeceirecl February 1.5, 1884.] 

 (Plates XL, XII.) 



The fact that there are already as many as 19 species in the 

 genus Sicijdium (to which I have had to add 5) seems to justify 

 an attempt to arrange the species into smaller groups, tlie members 

 of which may be found to be allied together by some convenient and 

 distinctive characters. Dr. Giinther, in his Eritish Museum Cata- 

 logue, divides this genus into two groups according as the anterior 

 teeth are, or are not, enlarged in the lower jaw. Making a further 

 use of the line of investigation which he here opened to us, I have 

 taken advantage of the opportunity of examining the characters of 

 the teeth in the specimens in the British Museum. 



I find that the teeth of the upper jaw, when subjected to a mag- 

 nifying power of some 200 diameters, are of one of four distinct 

 forms, viz., unicuspid, bicuspid, and two kinds of tricuspid. 



In the first grouj), or that in which the teeth are unicuspid, and 

 of which S. phtmieri may be taken as typical, the teeth (Plate XII. 

 fig. 5) are simple, slender, with the distal half bent inwards at or 

 nearly at right angles. In the second, or bicuspid group, as in 

 S. j)ii(jnans, n. sp., the teeth (Plate XII. fig. 7) are curved inwards 

 and have their extremities bilobed and shaped like the anterior part 

 of a pig's hoof. lu the third group, as an example of which a tooth 

 o{ 8. gymnoyaster, n. sp., is figured ^Plate XII. fig. 6), the teeth 

 are tricuspid and trident-shaped, the lateral lobes long, the middle 

 short and, as it were, suspended between the extremities of the 

 former, so that it soon becomes worn away, and the tooth is then to 

 all appearance bicuspid. I have not found these two last types of 

 tooth in any as yet described species which I have had the oppor- 

 tunity of examining. In the iburth and last group, as in 8. tceni- 

 vrum, the teeth (Plate XII. fig. 8) are also tricuspid and trident- 

 sliaped ; but all the lobes being of nearly equal length aud strength, 

 the teeth retain this shape until quite worn down. 



SiCYDIUM, C. & V, 



Sinjdium, Cuy. & Val. xii. p. 167; Giinth. Cat. Fish. iii. p. 91 

 (part); Day, P. Linn. Soc. xiii. p. 140. 



Sinjdium et Sicyojiterus, Gill. Proc. Ac. Nat. Sc. Philad. ISGO, 

 p. 101. 



Proc. Zool. Soc— 1884, No. XI. 1 1 



