﻿35 73 



like oviduct (od), which follows the dorsal surface of Ihe recluiu to the genital 

 opening behind the anus. The testis is also unpaired {A. strigata), like the ovary 

 in external appearance and with the vas deferens following the same course as 

 the oviduct. 



The kidneys (re) arc fused posteriorly into one body which reaches back- 

 ward to the rectum; at about the anterior end of the genital organ this body 

 divides into two weak and thin parts which accompany the cardinal veins. Whether 

 they follow these righl forward I have not been able to determine with certainty; 

 but there is a "head-kidney" round these veins anteriorly before they open into 

 the ductus Cuvieri. This head-kidney is traversed anteriorly by the large nerves to 

 the pectoral fins. It is most probable that only the posterior, voluminous part is 

 functional; as is usually the case in lishes the caudal vein enters into this posterior 

 kidney. I have not been able to find a urinary bladder. 



A plentiful, j^ellowish fatty tissue is developed along the whole of the ventral 

 margin, above the transparent ventral keel ; also dorsally above the anterior end 

 of the genital organ, between this and the hind part of the swim-bladder^. 



Ceiitrisciis scolopax. 



The appearance of this fish is so well-known, that I need simply refer in 

 regard to it to the figure on Plate I, fig. 3. 



Exoskeleton. 

 In contrast I o AmphisHe, Cent risens is covered by scales. These are present 

 not only on the whole of the body but also on the head, even on the long, tube- 

 like snout, on a great part of the eye, especially its posterior part; further, on the 

 anterior dorsal fin and on the fin-rays of the other fins. A number of spinous or 

 sculptured ridges project up through the scaly covering; on the head especially 

 there is a strong ridge from the upper corner of the gill-opening along the frontal 

 margin over the orbit and further above the nostrils out to the base of the snout 

 (PI. I, fig. 3); a second is continued from the anterior, lower border of the orbit 

 forward under the nostrils and joins with the previous in front of these; a third 

 oblique ridge on the ascending branch of the preoperculum behind the orbit and 

 a fourth, weaker on the operculum (see PI. I, fig. 3) etc. On the body of the fish, 

 in line with the ridge on the head first mentioned, there is a very apparent ridge- 

 like strip over the trunk above the pectoral fin and running almost horizontally 

 or sometimes a little obliquely: from this lateral ridge arise others, short below, 

 longer above, the last passing up in front of the base of the large dorsal spine. 

 There is also a short, curved ridge (cl) round the root of the pectoral fin, and a 

 short ridge (scl) runs down towards the front end of this ridge from the junction 

 of the lateral body-ridge with the head-ridge. Lastly, the ventral margin in front 

 of the ventral fins forms a sharp edge and there is a similar but shorter edge 

 going towards the anus behind the groove in which the ventral fins can be hidden. 



10* 



