18 LOPHOBRANCHII. 



Genus 2. ACENTRONURA, Kp. 



Diagn. — The edge of the hack coincides with the upper tail- 

 ridge, forming one and the same line. Gill-opening situated 

 at the point of the occiput. No protuberances either on 

 the bod}- or tail. 



Descr. — No coronet, merely a sharpening of the occipital 

 bone, as in the hind-head. Borders of the orbits like the breast- 

 ring destitute of spines. Dorsal fin standing on an insigni- 

 ficant eminence. Tail furnished with an egg-pouch, as in Hippo- 

 campus. 



h 



1. Acentronura gracillima, Kp. 

 Hippocampus gracillimus, Fauna Jap. p. 274. t. 120. f. 



Descr. — Its length is about 3 inches. The head does not 

 exceed the body in height, and the tail is twice as long as the 

 distance from the anus to the breast-fin. The speckled back -fin 

 of 17 rays is sustained by four rings, two of them belonging to the 

 tail. In the tail the rings number from 42 to 45. Anal scarcely 

 observable. In the prevailing yellowish colour there are traces 

 of dark and dotted cross bars. 



In the Leyden Museum there are four females full of eggs, 

 and two males. 



Genus 3. GASTER0T0KEUS, Heck. 



Syngnathoides, Bleeker. 

 Solegnathus, Bleeker, nee Swainson. 



Diagn. — Edges of the expanded belly formed by the lateral 

 lines. No nuchal shield. Tail prehensile. Dorsal stand- 

 ing in a furrow on from 10 to 11 tail-rings. 



Descr. — Compressed snout longer than the head, shagreened 

 by deeply-cut lines and pits. Forehead concave. Upper border 

 of the orbit ending in a spinous point. Occiput somewhat 

 round, elevated, destitute of a coronet. The gill-opening situ- 

 ated next to the back piece, and furnished with a half ring of 

 bone. In the place usually occupied by the nuchal shield there 

 is a breadth of naked skin, covering the neck-sinews that sustain 

 the head in its nodding movements. Ventral surface of the 

 breast-ring concave in the middle, notched at the point, and 

 heightened on both sides at the attachments of the pectorals. 



