SCANDINAVIAN FISHES. 



PHYSOCLYSTI ELEUTHERO&MTHL 



PJiysoclysts ivitli the edge of the upper Jaw composed only of the comparatively free intermaxillary hones, with the 

 hranchial arches complete and the branchial lamince pectinated. No externally visible interclavicles. 



With the advancement of development in the Tele- 

 ostei the intermaxillary bones assume a more and more 

 important position in the formation of the upper jaw. 

 In the Eleutherognates the intermaxillary bones remain 

 indejjendent, whereas in the Plectognates they are united 

 with the superior maxillaries, at the same time as the di- 

 visions of the lower ja^v, the dental and the angular, coa- 

 lesce into one whole. The Plectognates, which are repre- 

 sented in the Scandinavian Fauna by only t^vo rare species, 

 Balistes and Orthagoriscus, are well qualified, as far as 

 tliis cliaracter goes, for a higher place in the system, 

 the coalescence of the jaw bones being an unmistakable 

 sign of a more highly advanced degree of metamor- 

 phosis. However, in other respects, — in the marked 

 development of the exoskeleton, combined with the slight 

 ossification of the endoskeleton — they have retained 

 so much that reminds one of more ancient types, 

 tliat liitherto they have generally been placed lowest 

 among tlie Teleostei. It lias been left to modern 

 systematists to correct this mistake, and to show their 



close relationship to the most typical Physoclysts". The 

 Eleutherognates differ from the Hemibranchii, \vhich are 

 represented in our Fauna by the sticklebacks, in the 

 completeness of their branchial arches as well as in 

 the absence of interclavicles, and from the Lopho- 

 branchii, in our Fauna the group of tlie pipefishes, in 

 the pectination of their branchial lamina;. 



In the Eleutherognates the strengthening of the 

 fins, especially of the dorsal and anal, by an increased 

 number of spinous rays, is one of the most regular 

 indications of an advanced stage of piscine development. 

 Consequently from the time of Cuvier onwards the 

 spinous-rayed Eleutherognates or Acanthopterygii have 

 generally been placed highest among the Teleostei. This 

 division of the Eleutherognates may be distinguished 

 by the fact that in the front part, at least, of the dorsal, 

 anal and ventral fins there are simple unarticulated and 

 undivided hard rays. Foremost among these fishes we 

 shall place a series of families of wliich the well-known 

 wrasses may l^e considered typical. 



LABROMORPHI. 



Eleutherognates with the lower pharyngeals united to each other. 



In tli(! systems of Johannes Mijller and most 

 subsequent ichthyologists, these fishes have been named 

 Pharyngognathi'' in consequence of the union of the lower 

 pharyngeals, a character l)y which Artedi also defined 

 liis genus Lahrus," and Clvier the family Labroides^. 

 The rest of the Eleutherognates might therefore well 

 l)e called Lysipharyngii, if there be need of a cor- 

 i-esponding name for them, thcnigh the difference does 

 not seem to be of sufficient importance to justify us in 

 I'cferring tlie Phai-yngognates to a special order, as 

 MiJLLER and Guntiier have done'. However, the Pha- 

 ryngognates ])0ssess oiu' ninrk of a special modification 

 nf the Acanthopterygian ty|H', which apjjears only occa- 



sionally in the Lysipharyngii. This is the fact that the 

 masticating power of the mouth and pharynx is in- 

 creased both by the union of the lower pharyngeals and 

 by the stronger teeth -with which these bones as ^vell 

 as the jaws are armed. This appai'atus has reached its 

 highest ])oint of development in the exotic family of 

 Parrot-^vrasses, as represented by the Scams and simi- 

 lar forms. 



If furthermore we have regard to the great splen- 

 dour of colour by which manj^ of the Pharyngognates 

 are distinguished, we seem fully justified in following 

 the lead of Sundevall,' who was the first to place the 

 Pharyngognates highest, as far as development goes, in 



« Cope, Trans. Anier. I'hilos. SdC, Pliilad., n. ser. vol. XIV, art. V, p. 458. 



^ MCllkh: Uber den B<iu unci die Gremen der Ganoidcn itnd iiber das natiirliche System der Fische, Abli. A. Berl.-Akad. 1844, 

 Pliy.s. Kl., p. 199. 



'' Artedi: Genera Piscium, p. .33. 



■* Cuvier: Regne Animal, nouv. ed., Tome II, p. 254. 



•■ MiJLLER, 1. c. and GUnther, Brit. Mus. Cat., Fish., vol. IV, p. 1. 



/ In the arrangement of the collection of fishes In the Royal Museum of Stockholm. Cf. Cope, 1. c, where the same view is taken. 



