292 2R 



Through the nerve-holes in the coalesced vertebræ only spinal nerves pass out. 



A transverse commissure connects the two sympathetic trunks just in front of 

 the rudimentary pronephros. 



Genital organs. The ovaries appear to be unpaired, suspended by a 

 mesoarium to the left side of the dorsal body wall. They are bandshaped and 

 reach from the posterior end of the body cavity to a short distance behind the 

 beginning of the intestine. Closer examination shows that two ovaries are present: 

 posteriorly they unite into a short common oviduct with the usual opening behind 

 the anus; above the rectum their double nature may be noticed, and as stated 

 above the intestinal artery passes between them; but soon they externally appear 

 quite coalesced ; transverse sections reveal their double nature, the inner cavity 

 being divided by a thin vertical partition. The numerous ovigerous lamellæ in 

 each half leave part of the wall of the ovarial chambers free; in the middle of 

 the fused ovarial band this free part is lateral, but behind and in front of the 

 middle it may be more ventral. The testes externally resemble the ovaries, 

 suspended by a mesorchium in the same position, band-shaped and of the like 

 dimensions; transverse sections show that the band is made up of two closelj' 

 joined gonads. 



The peritoneum is silvery. 



The axillary pore, behind the pectoral fin, mentioned by Günther appears to 

 be the opening of the duct of a secreting gland. The latter is richly provided 

 with blood vessels^". 



Syngnathidæ. 



In the second Volume (Part 2) of his great work on Fossil Fishes, published 

 between 1833 and 1843 (p. 275), L. Agassiz states that he has not been able to give 

 any special information about the skeleton of this interesting group for want of 

 preparations fit for examination ; neither could he fill up this blank through the 

 literature: "car je ne trouve nulle part une description détaillée du squelette et des 

 écailles des Lophobranches". 



Regarding the skeleton very nearly the same might be said to day: a com- 

 plete description, accompanied by the necessary illustrations is up to the present 

 date not to be found anywhere; although Duméril in 1870 gave a monograph or at 

 all events a detailed account of this group based on the material of the Musée 

 d'Histoire naturelle at Paris and of the whole literature then available*. The fullest 

 and most correct information is that to be found in the Scandinavian literature. 

 As early as 1850 Kröyer in his "Fishes of Denmark" has given several good and 



' Second (52) p. 619 says 1873: "Auguste Duméril a rassemblé dans sa quatrième sous-classe tous 

 les documents que nous possédons sur les lophobranches. J'espérais trouver dans ce travail consciencieux, 

 des observations nouvelles sur les parties centrales des pégases et des syngnathes, mais ces nouveaux 

 documents manquent encore à l'ichthyologie .... A. Duméril se contente de dire que le squelette des 

 lophobranches ne ditïère en rien d'essentiel de celui des poissons osseux. " 



