SOLENOIDS. 
49 
Family SCLENIDfE. 
I 
External bones of the head smooth, or the preoperculum and operculum slightly denticulated. Scales slightly denti- 
culated and extending more or less over the vertical fins. When there are two dorsal fins, the anterior, which is 
slightly spinous, is shorter than the posterior, soft-rayed fin ; when the dorsal films are united into one continuous 
fin, the same relation holds good between the spinous-rayed and soft-rayecl parts of this fin. The muciferous ducts 
belonging to the system of the lateral line very much developed in the bones of the head. Simple, conical teeth 
on the jaivs, but the palate and tongue without teeth . Ventral fins thoracic, with one spinous and five soft rays. 
As Gunther" has already observed, the system of 
the lateral line in its extension on the head in these 
fishes follows the same typical arrangement as in the 
rest of the Acanthopterygians ; it is only its high de- 
gree of development * 6 that, to some extent, may form 
a character of the family, though in Acerina and Boccus 
we find these sensory organs but very slightly less de- 
veloped. Connected with the continuation of the scales 
over some or all of the vertical fins, a character very 
common among the Scicenidce, by which they range 
themselves along with the Squamipinnes, we find the 
continuation of the lateral line over the caudal fin, some- 
times right to the hind margin. Another organ which 
is generally very highly developed in the Scicenidce, is 
the air-bladder 0 , which, by its longitudinal division or 
its appendages in the form of longitudinal tubes or trans- 
verse, simple or complex excrescences, is probably con- 
nected with the power which these fishes possess of 
producing sounds audible at some distance d . 
In form of body these fishes are not very unlike 
the Percoid family. The Scicenidce might be considered 
as Sea-perches with, as a rule, weaker fin-rays and scales 
and also without palatine teeth, did not the dental equip- 
ment of two North American genera ( Haploidonotus 
and Pogonicis ) call for special notice on account of the 
strength of the pharyngeals, which is further increased 
by the coalescence of the inferior pharyngeals, else a 
character proper to the true Pharyngognat.es. This form 
of the pharyngeal dentition — obtuse grinding teeth 
(molars) arranged like the stones of a pavement — reap- 
pears in the jaw-teeth of the fishes belonging to the 
Sparidce. Another likeness between certain Scicenidce 
and the Sparidce is the circumstance that, though in 
the former the preorbital bones themselves do not cover 
the maxillary bones, it is true, still this is done by a 
dermal flap from the suborbital ring, when the mouth 
is closed. The Swedish name for the family, Hafgcjs- 
fishar (Sea Pike-perches), which has been introduced by 
Nilsson, is a suitable expression for the likeness of 
these fishes to the Perches, a likeness which does not 
vanish in their way of life. They are shore-fishes, 
though many of them, being excellent swimmers, are 
widely spread throughout the temperate and tropic parts 
of the ocean, and, like the genus Boccus, they some- 
times make their way to fresh water at the mouths of 
large rivers or higher up the stream. The genus Ha- 
ploidonotus, which we have just mentioned, and several 
species of other genera have their constant abode in 
lakes. In the Mediterranean the Scicenidce have been 
known and valued from time immemorial; in the Red 
Sea, according to Gunther, they are wanting. Accord- 
ing to the same author the family includes about 130 
species, distributed among 12 genera; Jordan and Gil- 
bert 0 , however, assume no less than 25 genera. In the 
Scandinavian fauna only one of these genera can be 
adduced, and that only as an occasional visitor. 
“ Brit. Mus. Cat. Fish., II, p. 287. 
6 Cf. Cuv., Val., Hist. Nat. d. Poiss., pi. 140. 
c Cf. Cuv., Val., 1. c., pi. 138 and 139, and Gunther, Study of Fishes , pp. 142 etc., or Handb. d. Ichth., pp. 95 etc. 
d Cf. W. Sorensen: Om Lydorganer hos Fiske. Kbhvn 1884, pp. 162 etc. and the passages there referred to. 
e Syn. Fish. N. Amer., Bull. U. S. Nat. Mus., No. 16, p. 566. 
Scandinavian Fishes. 
7 
