Homosteus, Asmuss, compared vnth Coccosteus, Arjassiz. 57 



Hugh Miller Collection. A similar bone supporting three 

 smaller interspinous elements was described and figured by 

 Sir Philip Egerton in Tristichopterus} 



As regards the sioecies of Ifomosteios, which has been under 

 consideration, no specific name was given to it by Hugh 

 Miller. By Morris ^ it was catalogued as the " Aste7'olepis 

 Asmusii " of Agassiz, but I know not on what ground. 

 Certainly I can find no resemblance between the sculpture 

 of the surface of the plates of A. Asmusii, as given in Agassiz's 

 figures, and that which characterises the present fish in 

 which the tubercles are small, sharply defined, with promi- 

 nently stellate bases, and for the most part closely placed. 

 Nor can it be identified with the species of Hoinostens 

 described ])y Asmuss from Dorpat, and so I would propose 

 that for the future it be known as Homosteus Milleri. 



Explanation of Plate. 



(In all the figures tlie same letters refer to the same things.) 



9«. 0., median occipital, g. o., external occipital, m., marginal, c, central. 

 2)t. 0., post-orbital, p. o., pre-orbital. ^j^. e., posterior etlimoidal. a. e., 

 anterior ethmoidal, p. mx., premaxillary. n., nasal opening, vi. cL, 

 median dorsal, a. d. I., anterior dorso-lateral. p)- ^- ^■■> posterior dorso- 

 lateral, a. I., anterior lateral. ^;. I., posterior lateral, i. I., interlateral. 

 a. V. I., anterior veutro-lateral. ^j. v. I., posterior ventro-lateral. p. m. v., 

 posterior median ventral. A, b, c, three facial plates lying below the 

 margin, anteriorly of the cranial shield of Homosteus. 



Fig. 1. Sketch of a specimen of Homosteus Milleri, Traq., in the John Miller 

 Collection, Museum of Science and Art, Edinburgh. 



Fig. 2. Kestoration of the top of the head in Coccosteus decijnens, Ag. The 

 dotted lines indicate the distribution of the grooves of the lateral-line 

 system. 



Fig. 3. Sketch of a specimen of Coccosteus minor, H. Miller, from Thurso, 

 the vertebral column omitted. Hugh Miller Collection. 



^ Dec. Geol. Survey, vol. x. , p. 52, plate 5. 

 ^ Catalogue British Fossils, p. 318. 



