2-48 MESSES. HANCOCK AND HOWSE 



"The pedicle of the tail is remarkably narrow, only about a 

 line broad ; the deep-forked fin is proportionally very large. Of 

 both lobes the extremity is wanting ; but it seems that the upper 

 lobe was not much longer than the lower, which is a little broader. 



"There is, as mentioned before, no trace of the scales." 



In Miinster's figure of P. Althausii, the posterior part of the 

 body, allowing for the slightly different state of preservation, 

 much resembles ours. The form of the abdominal cavity, 

 bounded in front by the " ribbon-shaped process," and posteri- 

 orly by the abdominal rod, is identical. The position of the 

 pectoral fin is also the same, though thought by Munster to 

 have been disturbed and pushed upwards out of its true posi- 

 tion. The prolongation of the dorsal fin is destroyed, as in 

 most of our specimens ; and the bones of the head are much 

 displaced, and moved downwards and backwards towards the 

 ventral cavity ; but these bones are said to be smooth and with- 

 out striae or granulations — a character which at once distin- 

 guishes this fish from Platysomus, in which the bones of the 

 head are always more or less ornamented with granulations or 

 striae. 



In Miinster's example the anal fin is finely preserved, and 

 shows very distinctly its continuation to the tail ; but by dis- 

 placement and pressure of the bones of the head downwards, 

 the ventral fins, which Munster saw, but could not describe 

 rightly on account of the disturbed state of his specimen, have 

 been pushed backwards, and brought nearly into contact with 

 the anal fin ; and thus one of the striking peculiarities of Doryp- 

 terus (the thoracic or jugular position of the ventrals) remained 

 till now unobserved. It will, we think, be admitted by every 

 one who carefully collates Miinster's figure and description of 

 P. Althausii with those of Germar's Dorypterus Hoffmanni, that 

 they are perfectly identical ; and we adopt the latter name for 

 the species, as it has a slight precedence in order of description, 

 and was, besides, more strongly characterized than the former. 



The German specimens of Dorypterus were obtained from the 

 Kupferschiefer of Bichelsdorf and the Eisleben district, where 

 it appears to be very rare. 



