128 Reviews — Pakeontographical Society. 



anterior portion, it is impossible to compare it with Newberry's in 



detail. The two seem to be of about the same size. 



The anterior clorso-lateral (ADL.) is shown in ventral aspect, and is 



not well preserved at the sides. It does not differ from the same 



element in Dinichthys. 



The jaw elements are represented by both mandibles {Mnd.), the left 



maxilla {Mx.), and the left preinaxilla(P.»i#.). The mandibles are of the 



typical stenognathous form, that is to say, greatly elongated and very 



slender. The left is shown in inner aspect and the right in outer. The 



maxillary has a cutting edge corresponding to the elongated cutting 



portion of the mandible. The premaxillary is shown in inner view ; 



it agrees almost exactly both as to size and form l with the corresponding 



element figured by Newberry in his D. Gouldi. 



Hence it appears that the specimen which has been described as 



I). Gouldi, and the mandibles which have been described as Stenognathus 



corrugatus and D. gracilis, really belong to one and the same species. 



This should be known as S. Gouldi, the specific name Gouldi having 



priority , 



EXPLANATION OF PLATE VIII. 



Fig. 2. Small slab exhibiting a pair of mandibles, two upper dental plates 

 (the dark elements seen in front of the mandibles) and fragments, of 

 a small specimen of Mylostoma, named, in manuscript, by Dr. William 

 Clark, Brontichthys. x |. Brit. Mus.i P, 9332. Cleveland Shale (Upper 

 Devonian) : Ohio. 



FlG. 4. Selenosteus brevis (Claypole). Type of Titanichthys brevis; slightly 

 less than x A. Brit. Mus., P. 9330. Cleveland Shale (Upper Devonian) : 

 Ohio. AVL. anterior ventro-lateral ; CI. clavicular; Cran. left half of 

 cranium, seen from within ; Mnd. mandibles ; MO. median occipital 

 element of cranium, from within. 



FlG. 5 and outline, Text-fig. 6. Stenognathus Gouldi (Newb.). Slab of shale 

 showing disarticulated plates of one individual, x A. Brit. Mus., P. 9335. 

 Cleveland Shale (Upper Devonian) : Ohio. 



REVIEWS. 



I. THE PALiEONTOGEAPHICAL SOCIETY. 



rpHE Palaeontographical Society's volume for 1910, which was 

 L issued at the end of January, 1911, contains instalments of the 

 monographs of Carboniferous and Chalk Fishes, Cretaceous Lamelli- 

 branchs, and British Graptolites, besides a small complete monograph 

 of British Carboniferous Arachnida. It is illustrated in the usual 

 sumptuous style by twenty-eight plates, some prepared by lithography, 

 others by collotype process. 2 Dr. Traquair's new part of Carboniferous 

 Palseoniscidce is especially welcome, and the text is now as far 

 advanced as the plates. After completing the description of Cyclop- 

 tychius, it deals with the numerous species of Rhadinichthys. A new 

 restored figure of It. ornatissimus is given ; and Mr. James Green's 



1 In Newberry's Paleozoic Fishes of North America (pi. ix, fig. 2), this 

 element is figured in outer view, but not quite correctly. It represents a second 

 cusp which in reality does not pertain to the specimen, but is an adherent 

 superimposed fragment. The line from the point of the tooth to the postero- 

 lateral termination of the element is gently convex, but quite smooth. 



2 And the text-figures are very numerous throughout the volume. 



