284 18 



interneural) is much smaller, and the sculpture of the upper face shows a some- 

 what different pattern. 



Behind the unpaired nuchal plates paired, symmetrically arranged structures 

 appear in the shape of a double series of long, thin, laterally compressed bones 

 on each side, running along the tips of the spinous processes to the end of the 

 tail, only interrupted by the dorsal fin (PI. II, fig- 9 td); a similar, ventral, double 

 series occurs along the inferior spines of the tail, beginning just behind the anal 

 fin. Each member of both series extends over a number of (4, 5 or more) vertebræ; 

 the uppermost rows are situated just below the skin (in alcoholic specimens they 

 may be more or less visible through the skin); in Fistularia pedmba they so to 

 speak embrace the row of median scales. The two above-mentioned prolongations 

 from the 3rd nuchal evidently belong to the same system. That these bones are 

 ossified tendons or ligaments is hardly to be doubted; they apparently are struc- 

 tures similar in kind to the subdermal ossifications which are so richly developed 

 in Aulostoma. 



Ossifications of a similar nature are further the two large, flat bones, which, 

 fastened to the epiotics of the skull, are situated along the back, one on each side 

 of the nuchal plates. The upper face is sculptured on the anterior half and to a 

 great extent visible through the skin; from the lower face, near the inner margin, 

 of the posterior half originates a thin vertical lamella, enlarging the surface for 

 muscular attachment. Like the corresponding bones in Aulostoma these structures 

 are simply ossifications of tendons of the anterior part of the dorsal lateral muscles. 



16 bisegmented interneurals support the dorsal fin. The foremost is short, 

 about horizontal, and its lower end joins directly the dilated upper end of the 

 spinous process of the first caudal vertebra; the following are interposed as usual, 

 singly or in pairs or even three, between thé spinous processes of the supporting 

 vertebræ. With each lateral face of the first interneural an ossified tendon of the 

 set in front of the fin is coalesced or firmly united; the like is the case with the 

 hindmost interneural, a pair of tendons from the set behind the fin being joined 

 with it. 



The anal fin is supported by 15 interneurals, also bisegmented and with 

 ossified tendons attached to the hindmost member. The first interneural is situated 

 in front of the inferior spine of the first caudal, the following are interposed 

 between the spines of 10 vertebræ. 



The dorsal fin has 17 — 18 rays, the anterior 3, especially the foremost, 

 extremely short; the anal fin has 16—17 rays, the anterior 2 very short'-. 



The caudal fin has 10 — 11 -j- 2 + 10 — 11 rays, the 2 middle ones being ex- 

 tremely elongated, forming the peculiar filament. All the rays of the unpaired fins 

 are laterally flattened, unjointed (but composed of two lateral halves), also the two 

 composing the caudal filament. Only the caudal rays nearest to the caudal filament, 

 2 or 3 above and below this, are branched. The lateral line is continued along 

 the filament almost to the lip, enclosed in a series of slender bony tubes; the 

 presence of the latter may produce an appearance of joints '^. 



