ON DOEYPTERUS HOFFMANNI. 267 



left. The dorsal fin (a), too, is very imperfect, three-quarters of 

 an inch only remaining. The short anterior plates, or fulcra 

 (a"), are pretty distinct ; but the merest traces are found of the 

 narrow posterior part. The greater portion of the anterior divi- 

 sion of the anal fin (b) is well preserved, and the narrow poste- 

 rior part (6') is determinable throughout its length. The tail is 

 much injured, but lies, as in all the other examples, spread out, 

 the two lobes being strongly defined. 



"We have now only a few concluding words to say as to the 

 place this curious fish should occupy in the classification. We 

 know of no family with which it can be associated, though it 

 is undoubtedly closely allied to the Pycnodonts ; and of these 

 perhaps it approaches most closely to Gyrodus and Microdon ; 

 but while in Dorypterus the head-bones are smooth, they are in 

 most of the Pycnodonts granulated or otherwise ornamented ; 

 and our fish likewise differs from them in the absence of the 

 usual body-scales. 



The large and upward -shutting mouth, too, is not found in 

 the Pycnodonts ; and the apparent absence of the strong cha- 

 racteristic teeth of that group is noteworthy. Had such teeth 

 existed in the fish under discussion, some trace of them would 

 assuredly have been observed, since we have seen that the jaws 

 are pretty well preserved in two or three of our specimens. It 

 is probable, therefore, that the dental organs were small and in- 

 conspicuous, if they existed at all. The enormous development 

 of the dorsal fin and the forward position of the ventrals are 

 significant facts. The latter is particularly worthy of notice, 

 especially when we consider that we have in this paleozoic spe- 

 cies the earliest thoracic fish known in the geological series. 

 And further, Sir Philip Egerton states, in a letter with which he 

 has lately favoured us, that he "is not cognizant of any fish in 

 strata older than the chalk having the fins thoracic or jugular." 

 On the whole, then, we confess ourselves at a loss to determine 

 where to locate Dorypterus in the system. Is it not the repre- 

 sentative of a distinct family having a certain relationship to the 

 Pycnodonts ? This we must leave for the determination of those 

 more conversant with ichthyology than we ourselves are. 



