FISHES. 289 



among fishes, for progression. According to Mr. Goode, " the propelling force is 

 exerted by the dorsal and anal fins, which have a half-rotary, sculling motion resem- 

 bling that of a screw propeller." The caudal fin merely acts as a rudder, except in 

 cases of emergency. 



The trunk-fishes, on account of their strange form, have been long the objects of 

 tlie collector's efforts, and even more so in past times than now. In the early part of 

 the last century it appears that fishes of this kind were on exhibition at prominent 

 taverns in Europe, and Artedi mentioned several of those in which he saw specimens. 

 As a result of this passion, says Mr. Goode, "no group of tropical fishes is so thor- 

 oughly worked out in the writings of the fathers of natural history as this one. Over 

 two hundred years ago, every species of trunk-fish now taken from the Atlantic was 

 known to and described by the naturalists of northern Europe, and it is a well-deserved 

 tribute to their discrimination as zoologists to say that none of the many efforts which 

 have since been made to subdivide their species have been at all successful." 



The trunk-fishes are, to a limited extent, used as food. It is said that in the West 

 Indies and in Florida they are " sometimes baked in their own shells, and, when cooked 

 in this way, are considered by many persons to be great delicacies." Their use is 

 sometimes accompanied with danger, however ; for " there are instances on record of 

 serious cases of poisoning which liave resulted from eating them. These cases occurred 

 in tropical countries, where the flesh of fish often becomes deleterious after a few 

 hours' keeping." 



Sub-Oeder III. — Gymnodontes. 



By far the most grotesque and unlike any true fishes are those belonging to the 

 present sub-order. The body is enclosed in a skin which is almost sack-like, and which 

 is capable of great distension, especially in the ventral region. The scales are reduced 

 to very small spines (except in the Triodontidse) imbedded in the skin, and some- 

 times almost or absolutely wanting. No spinous dorsal is developed, there being 

 only a soft fin ; the ventral fins are entirely wanting. The teeth are not represented as 

 such, but are consolidated with the jaws, and these are in one piece above or below, or 

 in two pieces in one or both jaws. Several well-marked families belong to this group. 



The family of Teiodontid^ is simply noteworthy for the dermal covering, which 

 resembles that of the Balistinse, and also for the long, movable pelvis, which like- 

 wise recalls the Balistinse. 



The chief family of the sub-order is that distinguished as Teteodontidje. In 

 these the jaws are in two teeth-like pieces, both above and below ; and the dorsal and 

 anal fins are moderately developed, as is also the caudal. The skull as well as 

 the other portions of the skeleton have a number of peculiar characters, which verify 

 the validity of the group. In this group we have the dilatability of the abdomen 

 often well manifested. In some species the belly is very extensible ; and the names 

 swell-fish and puffer have been given in allusion to it. The species are quite nume- 

 rous, and representatives of two genera are found along the eastern American coast. 

 They are,. however, only summer residents, and have traveled or been wafted from 

 warmer seas. On account of their remarkable form they attract the attention of 

 most dwellers by the sea, and therefore have received numerous popular names, such 

 as swell-fish, bottle-fish, bellows-fish, egg-fish, globe-fish, swell-toad, blower, box-fish, 

 etc. Two species are tolerably abundant along the eastern American coast. 



VOL. III. — 19 



