27 293 



correct descriptions; later Lilljeborg (1891) and Smitt (1895) have supplied more 

 or less complete accounts of the skeleton; regarding the composition of the skull, 

 these authors especially Smitt have interpreted several features more correctly than 

 any previous or later author; but they have not avoided some grave errors. 



I may add that these Scandinavian authors also give much good information 

 about the anatomy of the soft parts, and it ought to be mentioned that in 1833 

 Retzius already described the main anatomical features of the most common 

 species of northern pipe-fishes so completely, that in several points the investigations 

 published as late as 1902 by Huot do not contain much that is really new. The 

 few remarks about the osteology in Huot's paper contain several errors; and the 

 same may be said of the papers published by Mc. Murrich, Schaff, Cope, Jordan 



& EVERMANN, SwINNERTON CtC. 



As to the systematic position of the Lophobranclis I shall here only mention 

 that Cuvier in 1817 (Règne animal 1. Edit. II. p. 155) gave them rank as one of his 

 8 Orders or main divisions of the Class Pisces; he did so essentially on account 

 of their gills. This elevated rank and isolated position has often been attacked ; 

 every one who has really examined their gills, has seen that these do not sub- 

 stantially differ from those of other Teleosteans; Cuvier himself has realized this 

 fact, and so did Rathke, Retzius, Ryder and several others. Nevertheless their 

 isolated position is still maintained by many authors. Without entering further 

 into any discussion of the systematic point I might only mention that in 1908 

 (23 b) I have expressed as my view, that the true Lophobranchii (or Syngnathidæ), 

 the Solenostomidæ, the Fistularidæ, Aulostomidæ and the Centriscidæ form one 

 natural group; and I have briefly pointed out some characters in the cranial struc- 

 ture which seem to me to raise this view above doubt. 



The true Pipefishes, the Syngnathidæ, are a fairly homogenous family, natur- 

 ally divided into two groups, one for which the well-known genera Siphonostama 

 and Syngnathus, the common pipefishes of European and N. American coasts, may 

 serve as types, and one containing forms such as Hippocampus, the Sea-horse. 



Proceeding to the osteology of this family, I think it most convenient to de- 

 scribe in some detail one type, and afterwards to point out some of the more 

 essential features in which other forms deviate from this type. As type we may 

 consider Siphonostoma typhle, a species which is to be found everywhere in the 

 zostera-region of the Danish coasts, or at similar localities of the Baltic and the 

 North Sea. 



Siphouostoma typhle (L.). 

 Exoskeleton. 



The dermal armour of Siphonostoma and other Syngnathids has often been 

 described and its main features, I think, are so well known that a recapitulation 

 here seems superfluous. Only regarding the nuchal plates and the composition of 



38- 



