260 LOWER VERTEBRATES. 



somewhere about three hundred in number. It comes in on " the border line between 

 food and refuse fishes ; " but " some people consider the flesh as very fine and whole- 

 some." 



The forms that come up next for review have been almost universally associated with 

 the cod-fishes ; but they are really but distantly related, and are nearer the preceding. 

 The Brotulid^ are a family of which few species were known till the era of deep- 

 sea dredging and trawling, but now there are many. The body is elongated, and 

 tapers backwards to the end of the tail ; small scales are immersed in the skin ; the 

 head is diversiform, but always has a large mouth ; the branchial apertures are gener- 

 ally ample ; the dorsal and anal are long (the dorsal especially), and generally covered 

 with loose skin and scales ; a caudal is developed, but narrow ; the ventrals are jugu- 

 lar, very narrow, and, generally, with two rays. 



Numerous species representing many genera, some possessed of very curious char- 

 acters, inhabit the depths of the sea. Some have stout spines about the head and 



Fig. 147. — Encheticphis tenuis, natural size, and bead enlarged. 



shoulders ; and the inhabitants of very deep water are very loose and flaccid in 

 appearance. Very few live in water of moderate depth. Among them are the name- 

 giving genus of the family {Brotula) and a species found along the Californian coast 

 {Brosmopliycis or Dinematichtliys margmatus). Only two others are specially note- 

 worthy ; they are blind fishes inhabiting fresh water in certain caves of Cuba ; Lud- 

 fuga subterranea and Stygicola dentata are their names. 



Closely related to the Brotulidae are some fishes distinguished by the position of 

 the ventrals at the chin, or between the rami of the lower jaw. These are the Ophi- 

 DHDJE. On account of this advanced position of the fins, they were supposed by the 

 old naturalists to be a pair of bifid barbels, and the fishes were placed with the eels, 

 as apodals. Most are of little value and small in size, but some species of the south- 

 ern hemisphere become quite large and are in some repute for their flesh. One living 

 in the sea round New Zealand ( Genypterus blacodes) is known as the ling or cloudy 

 bay-cod, and reaches a length of five feet and a weight of fifteen to twenty pounds ; 

 " it has white, flaky flesh that takes salt well:" 



Finally we have a few fishes constituting the family Fieeasferid^, still smaller 

 and more tapering backwards than the preceding, and differing from them by the en- 

 tire absence of ventrals. They manifest a very singular phase of fish-life, for they 

 chiefly live in the interior of other animals, especially holothurians. They have been 

 especially studied by Prof. Carlo Emery, who watched their movements, and tells us 

 how they enter into the holothurians. When free in the water, the fish swims head 

 downwards, with tail curved toward the back, by undulatory movements of the anal 

 fin. Coming to a holothurian lying at the bottom of the water, it eagerly seeks the 



