446 



CONTRIBUTION TO THE 



for Ashes with connate inferior pharyngeal bones), Physostomi i Malaoopterygians of Cuvier, neai'ly), Plectognathi and 

 lophobranehii of Cuvier. The groat number of facts in the anatomy of Ashes added by Miiller, constitute him the 

 father of modern ichthyology. 



Prof. Gill, in 1861, adopted many of the divisions of Miiller, and rejeoted some; others were newly proposed. 

 But four sub-classes were recognized, the Dermopteri which included also Miiller's Leptocardii, (be Elasmobrancliii, 

 equivalent to Mailer's Selachii ; the Ganoidei, including here Miiller's Dipnoi, and Hie Teleostei. Six orders were 

 attributed to the last sub- class, which were quite different from those of Miiller. Thus adopting the Pleciognathi 

 and Lophobranehii, the cat fishes were erected into a new order, the Nematognathi ; the eels into another, Apodes, 

 and the ribbon-fishes doubtfully assigned to another, called Lemniseati. The remainder of the bony fishes were 

 regarded as constituting the sixth and highest, or Teleoeephali. To this as sub-orders were referred, the old orders 

 Physoclysti ( Aeanthqpteri Pharyngognathi and Anacanthini of Miiller), and Physostomi of Miiller ; -with the new ones 

 Ueterosomata (the flat fishes), and Ewrttognathi (the Cyprinidse). 



Subsequent to this publication, important contributions to the system have been made by igassiz, Kner, biifken, 

 Gill, Huxley, etc., which will be noticed at the proper time. 



The writer having been engaged in an examination of the osteology of the bony lislics, and general anatomical 

 structures of the whole, has proposed to point out some further modifications of the received system, which he be- 

 lieves will render if a, closer reflection of nature. There are some portions of the skeleton which have been to a great 

 exlenl overlooked in seeking for indications of likeness and difference of types, and the estimation in which many 

 known characters are held, maybe much altered on the study of extended material. The skeletons on which the present 

 study is made are 1000 in number, 200 belonging to the Academy of Natural Sciences, of this cify, and 800 to the 

 writer, being the collection made by Professor Joseph llyrtl, the distinguished anatomist of Viouna. This collection 

 lias been long known to anatomists in Europe as the most, beautifully and reliably prepared in existence, and as 

 valuable as any, for study, on account of the fulness of the representation of the various types. 



2. Special on the Ganoids. 

 Recurring to Miiller's system, the writer adopts, as characterized beyond dispute, his sub -classes or orders of Lep- 

 tocabdii, Debmoptebi, Selachii and Dipnoi, and conflnes himself at present to the recent Qanohlea and leleosteL 

 I have shared in the doubts occasionally expressed by ichthyologists, as to the essential distinction of thoso latter di- 

 visions, and an examination info fin; osteology, with reference to (Ids point, confirms the doubts raised by a study 



of the soft parts. As is well known, Miiller distinguished the Ganoidea by Ihe muscular bulbous arteriosus con- 

 taining numerous valves, and (lie connection of the optic nerves by commissure rather than by decussation. He 



added several other characters, knowing them, however, to be shared by various other orders and subclasses, and I 

 have selected the only two which seemed to be restricted to the division. Their restriction to it, however, is only 

 apparent, and Kner points out that the peculiarity of the optic commissure is shared by some Physostomi, and that the 

 difference between the number and character of the valves of the bulbus in Lepidosteus and Amia is quite as great 

 as that existing between Amia* and some of the Physostomi. After an examination of tbo skeleton, it is obvious 

 that, in this part of the organism also, there is nothing to distinguish these fishes from the Teleostei of Miiller. It 

 is true that each of the genera referred to it possesses marked skeletal peculiarities, but they are either not common 

 to all of them, or are shared by some of the Physostomi. If, on the other hand, wo compare those genera with each 

 other, differences of the .greatest importance are observable, which at once distinguish two divisions, one represented 

 by Polypterus, the othor by Lepidosteus and Amia. 



In the first, place, the basal radii of the pectoral fins of Polypterus are observed to bo excluded from articulation 

 with the scapular arch by the intervention of throe elements, whioh form a pedicel or veritable arm for the fin ; 

 in Lepidosteut and Amia the radii are sessile on the scapular arch as in ordinary fishes. The ventral flns present 



a like difference ; the basal radii are long, and four in number in Polypterus. In the other two genera they are 

 absent, excepting one rudimenfal ossicle on the inner basis of the tin (two in Lepidosteus), precisely as in the I'hysos- 

 I onions families Mvnnyritlii', CatostomidiM, etc. If we examine the branchial apparatus, we iind an undivided cerafo 

 hyal, threo branohihyal arches, ami no inner and but two outer bones of (be superior bramliiliyals present in 

 ' See I-" i -.- 1 n . 1 1 1 , ■ Nonr.ul.aii Ainiiiiu calvam. Tab, I, fig, 10, 



