268 Mr. W. S. Kent 07i a new Species o/"Sagitta 



characters, and has now been found attached to a jaw the 

 surface-ornament of which perfectly accords with that of the 

 above-mentioned remains. However it may be Wiih. RMzodus, 

 it would therefore seem impossible not to adopt the conclusion 

 that all these specimens belong to one and the same fish ; and 

 the tooth proves that they can have nothing to do with RM- 

 zodus. For this fish, then, so characterized, and which seems 

 to us to be generically as well as specifically new, we propose 

 the name Archichthys sidcidens. 



We must add, before concluding this note, that the teeth of 

 our new fish sometimes measure two and a half inches in length 

 and are upwards of an inch wide at the base, and that upwards 

 of a score of specimens of it have occmTcd at Newsham. It is 

 therefore pretty certain that they never attain the dimensions 

 of those of Rhizodus, from which they can always be distin- 

 guished by their rotundity, the total absence of cutting- 

 edges, and the fine striation of the surface, though they are 

 folded at the base in a manner similar to those of that great 

 enigma. 



We may also add that thirteen opercular plates have been 

 found, some being quite perfect and in excellent condition. 

 The scales, too, are not by any means rare in the same loca- 

 lity. The remains, then, of this fish being so abundant, the 

 non-occurrence of the large Rhtzodus-tooth is very significant. 



XXVIII. — Oil a new Sjjecies o/'Sagitta fi'om the South Pactjic 

 (S. tricuspidata). By Wm. S. Kent,>.Z.S., F.R.M.S., of 

 the Geological Department, British Museum. 



Some months since, Mr. T. J. Moore, the able Conservator of 

 the Free Public Museum, Liverpool, received from the South 

 Pacific, in company with Leptocephali and an infinite number 

 of other oceanic forms (the produce of surface-dredging on the 

 high seas), certain organisms of such a fish-like outward ap- 

 pearance, that they were consigned to the hands of a cele- 

 brated ichthyologist for identification. The peculiar armature 

 of their cephalic region plainly indicated, however, that, if 

 fish, they were very aberrant representatives of the class. 



The privilege of examining them having been afforded me, 

 the idea at once suggested itself that they belonged to that in- 

 teresting group, most closely approximating to the Annelida, 

 designated by Professor Huxley the Chsetognatha, and of 

 which Sagitta constitutes the single genus. 



Subsequent investigation substantiated the correctness of 

 the inference primarily arrived at, and at the same time de- 



