VOL. XV.3 PHILOSOPHICAL TEANSACTION8. 25^ 



few to the bottom of it, and there terminated : which probably serves for the 

 emission and reception of air at pleasure, to balance the body, according as 

 either its gravity, or that of the medium is altered. The received opinion that 

 fishes have neither reins nor bladder for urine, is from experience contradicted, 

 it being found by dissection, that few fishes want a bladder, none reins. The 

 situation of the appendices or blind-guts is observed to be different in fishes, 

 from what it is in other animals ; for in these they are situated at the end of 

 the guts, at least of the small guts; in those at the beginning, next the stomach. 



Next to the parts of fishes and their uses, many things are said concerning 

 the generation of fishes ; which is shown to be threefold, according to the three 

 chief kinds of fishes. For, 1 , the cetaceous kind (which are rightly called by 

 Latines belluae marinae, sea-beasts) generate exactly after the manner of vivi- 

 parous quadrupeds. 2. The cartilaginous kind somewhat resemble birds in 

 their manner of generation, for they breed large eggs, with distinction of yolk 

 and white ; only they do not lay them, but cherish and hatch them in their 

 wombs, and so bring forth live young ones ; as vipers, and perhaps some other 

 sorts of serpents do. 3. The spinose kind, (under which name are compre- 

 hended all other fishes beside the fore-mentioned,) conceive an innumerable 

 number of small eggs called spawn, which probably answer to the cicatriculae 

 in birds' eggs, and that (as is conceived) without any coition or copulation with 

 the male ; on which spawn, as soon as it is cast by the female, the male or 

 milter presently comes and scatters his milt or seed. 



In the last place is delivered a general division of fishes, according to the 

 characteristic notes of nature. As, 1, into the cetaceous kind, which in most 

 of their internal parts, the conformation of their brain, their manner of re- 

 spiration and generation, agree exactly with viviparous quadrupeds. 2. The 

 cartilaginous kind, by which name are not to be understood all sorts of fishes 

 that have gristles instead of bones, but those which Aristotle calls (rixd^n, which 

 are, as he phrases it, inwardly oviparous, breeding great eggs like to those of 

 birds, or rather serpents, but outwardly viviparous, laying and hatching those 

 eggs in their own bellies, and so bringing forth live young. 3. The spinose 

 kind, under which name are comprehended all fishes that are oviparous, or cast 

 their spawn, indeed all besides those belonging to the two foregoing genera. 

 Those of the cetaceous kind being but few, are not subdivided in this work. 

 The cartilaginous kind are divided into those that are long and round bodied, 

 called sharks and dogs ; and those that are flat and broad, which are again sub- 

 divided into suborbinate genera. The spinose fishes, which are the most numer- 

 ous, are divided into, 1 , the flat kind, which swim lying on one side ; as the 

 sole, plaise, &c. 2. The anguilli-formes, or eel-like fishes, that are long, 



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