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COCCOSTEIDJE. 305 



18G0. llomostius latus, E. von Eichwald, Leth. Rossica, vol. i. p. 1519, 

 pi. lvi. fig-. 2. 



Type. Portion of median dorsal plate ; University Museum, 

 Dorpat. 



The type species, known only from separately discovered bones 

 Median dorsal plate broader behind than in front, the posterior 

 margin only slightly convex ; forwardly directed process of anterior 

 dorso-lateral plate slender and pointed. 



Form. <$f Log. Lower Devonian : Livonia, and near PawlowsK, 

 Government of St. Petersburg. 



The following are plaster casts of the original bones from Livonia 

 in the University of Dorpat, and were presented by Sir Roderick I. 

 Murchison, K.C.B., about 1846. 



15142 a. The type specimen, being the middle and right lateral 

 portions of the median dorsal plate, wanting all margins 

 except the posterior ; described by Asmuss {op. cit. p. 35. 

 no. 5) as " scutum dorsale anterius," and the posterior 

 border regarded as anterior. 



15142 b. Imperfect left anterior dorso-lateral (Pander, fig. 2 11 ), de- 

 scribed by Asmuss (p. 36, no. 35) as right " adminiculum 

 laterale " of H. formosissimus. 



15142 c. Left postorbital (Pander, fig. 2 5 , Agassiz, fig. 2), described 

 by Asmuss (p. 38, no. 36) as right " os incunneatum " of 

 H. latus. 



15142 d. More imperfect example of the same bone, showing the 

 postero-lateral extension. 



15142 e. Middle and right lateral portion of hinder half of median 

 occipital, the type specimen of H. latus, Asmuss (p. 36, 

 no. 6), and described as left anterior portion of the " scutum 

 dorsale posterius." 



15142 f. Middle portion of median occipital, the type specimen of 

 H. cataphractus, Asmuss (p. 36, no. 7), and determined as 

 " scutum dorsale posterius." 



15142 g. Half of median occipital, and portion of adjoining left 

 lateral occipital, probably the basis of Pander's partial 

 restoration (fig. 2 9 ' i0 ) ; described by Asmuss (p. 37, no. 32) 

 as right " os multifixum " with " scutum dorsale poste- 

 rius " of H. cataphractus. 



15142 h. Outer portion of left lateral occipital, probably employed 



PAKT II. x 



