422 Reviews — Dr. 0. Jaekel — Armoured Palceozoic Sharks. 



of their labours; they have produced a book which will greatly 

 advance our knowledge of the higher Vertebrata, and must prove 

 most helpful to the student of Mammalogy ; nor can any Library of 

 reference be complete without this most excellent vade mecum. 



II. AkMOTJRED PALiEOZOIO ShARKS. 



1. Uebee Flossenstacheln odek Ichthyodorulithen im Allge- 



MEiNEN. By Dr. Otto Jaekel. Sitzungsb. Ges. naturf. 

 Freunde, Berlin, 1890, pp. 119-131. 



2. Ueber Menaspis, nebst allgemeinen Bemerkungen ueber die 



SYSTEMATiscHE Stellung ber Elasmobranghii. By Dr. Otto 

 Jaekel. Ihid. 1891, pp. 115-131, with Plate. 



3. OnACANTUUS BocHUMENSis, n.sp., EiN Traohtacanthide des 

 deutschen Kohlengebirges. By Dr. Otto Jaekel. Zeitschr. 

 deutsch. geol. Ges. 1890, pp. 753-755, PI. xxxvii. 



LAST month we had the pleasure of recording important progress 

 in our knowledge of some Palseozoic Elasmobranch skeletons, 

 due especially to the researches of Dr. Anton Fritsch among the 

 Pleuracanth fishes of the Bohemian Permian formation. On the 

 present occasion we are able to chronicle another interesting advance 

 in the study of allied forms, resulting from the renewed examination 

 of a fossil from the German Kupferschiefer described many years 

 ago by Giebel. It has long been known that certain representatives 

 either of the Elasmobranchii or of the Holocephali, in Palaeozoic 

 times, possessed a remarkably developed dermal armour. Hitherto,' 

 however, the portions of this armour have almost invariably been 

 found isolated, only few discoveries suggesting that they were fixed 

 upon the head and anterior part of the trunk of the fishes to which 

 they originally pertained. Quite recently Dr. Otto Jaekel has made 

 an interesting contribution to the subject by further extricating from 

 the matrix the supposed Elasmobranch fossil described and figured 

 by Giebel without name in the Zeitschr. gesammt. Naturw. Halle, 

 1856, p. 367, pis. iii, iv, ; and this is identified with a problematical 

 fish very inadequately described by Ewald in the Monatsber. k. 

 preuss. Akad. Wiss. 1848, p, 33, under the name of Menaspis armata. 

 The fossil in question is clearly and concisely described in the 

 second memoir quoted at the head of this notice, and Dr. Jaekel is 

 to be congratulated upon the success with which he has removed the 

 obscuring film of matrix which caused the vagueness in Giebel's 

 original figure. The specimen is but small — perhaps not more than 

 0'15 in length — and is interpreted as displaying the dorsal aspect 

 to the hinder border of the pelvic fins. The head and anterior part 

 of the trunk seem to have been comparatively broad and depressed ; 

 and the pectoral fins were evidently larger than the pelvic pair. 

 There are three lateral pairs of much elongated dermal spines, with 

 recurved tips, fixed upon the head ; and a single pair of Oracanthus- 

 shaped spines also occurs postero-laterally. Between the pectoral 

 fins there is placed another pair of smaller broad triangular spines ; 

 and in the skin of the back there are symmetrically disposed longi- 



