744 Retrospective Criticism. 



loose striated texture, but, where exposed in the recent ani- 

 mal, covered with a kind of enamel ; and within this, in each 

 jaw, are three or four rows of flattish teeth, loosely and rather 

 irregularly placed. — J. Couch. Polperro^ June 28. 1830. 



A Contribution to the History of the Propagation of the Eel 

 (Murcena Anguilla L.) (p. 313.), a?id Conger (Mt/rce^ria Conger 

 L.) — Sir, I have lately read that very pleasing book Jesse's 

 Gleanings in Natural History [briefly reviewed p. 374.], and I 

 noticed in it some opinions that I consider erroneous, parti- 

 cularly those on the propagation of eels ; and as you, p. 374., 

 call attention to Jesse's opinions on this subject, I request a 

 place for the following remarks : — 



The author endeavours to prove that eels are viviparous ; 

 that the young are contained within the intestines of the 

 parents ; and that they are sometimes bred in freshwater 

 ponds. I am convinced that all these notions are incorrect, 

 although they have existed for ages, and have been coun- 

 tenanced by many celebrated men. iThese opinions exploded 

 the more antiquated ones, that the creatures were bred from 

 putrefaction of dead eels, from particles scraped off from living 

 ones by their rubbing against rocks, from bits of horse hair 

 falling into water, from dew-drops, and from mud of ponds 

 and ditches animated by the sun's vivifying rays. The author 

 of Gleanirigs in Natural History certainly mistook parasitic 

 vermes [worms] for young eels ; and as he was aware that 

 similar creatures were found in other fish, I wonder that he 

 did not try whether they would wriggle and swim about in 

 water, as well as the little things did which he took from the 

 intestines of eels. If he had done so, I assure him that he 

 would have found them equally active and eel-like. 



If any one will take the trouble to examine the fat-like 

 fringe on the sides of the air bladder and kidneys of the eel and 

 conger, he may, with a common pocket lens, and often without 

 the aid of a glass, see an abundance of ova [eggs] from the 

 beginning of the year to about September. I attended a good 

 deal to the natural history of these fishes a few years ago, and 

 I was then in communication with a very distinguished person 

 (now no more), whose philosophic mind was much engaged on 

 this subject, and whose information would have been highly 

 valued by naturalists, if he had lived to give it to the world. 

 The following extracts from a communication which I made 

 to him in Feb. 1829, will, I think, be acceptable to many of 

 your readers: they contain the result of much patient in- 

 vestigation : — 



By examining every eel and conger that I could procure 

 between March and September, I traced the growth of the 



