446 THIRD REPORT 1833. 



importance of connecting pliysiological researches with anato- 

 mical details. 



In attempting to drown a small spider, new to naturahsts, 

 (which the author has named Erigone atra,) for the purpose of 

 taking its dimensions accurately by measurement, he was asto- 

 nished to find that at the expiration of two days, though it had 

 remained under water the whole of the time, it was as lively 

 and vigorous as ever. This extraordinary circumstance induced 

 him to submerge nimierous specimens of both sexes in cold 

 water contained in a glass vessel with perpendicular sides, on 

 the 21st of October 1832, in which situation they continued till 

 the 22nd of November, an interval of 768 hours, without having 

 their vital energies suspended. 



He has tried the same experiment with individuals of other 

 species, and some of them have preserved an active state of 

 existence for six, fourteen, or twenty-eight days, spinning their 

 lines and exercising their functions as if in air, while others 

 have not survived for a single hour. It is evident, therefore, 

 from these curious facts, that some spiders possess the power 

 of abstracting respirable air from water ; for though in the act 

 of submersion the spiracles are generally enveloped in a bubble 

 of air, yet so small a supply is speedily exhausted, and, indeed, 

 soon disappears. 



The external and internal organization of such species of 

 Araneidce as can exist for a long period of time under water 

 deserves to be attentively examined ; but those species which 

 the author has observed hitherto are minute, and it would re- 

 quire the hand and eye of an accomplished anatomist, assisted 

 by the most delicate instruments and powerful magnifiers, to 

 effect this desirable object satisfactorily. 



On the Reproductionofthe Eel. By William Yarrell, F.L.S. 



Sir Humphry Davy, in his " Salmonia," considered the 

 mode in which eels produced their young as a problem in na- 

 tural history not then solved, the more general opinion being 

 that they were viviparous. 



The paper commences with a recital of the opinion^ of various 

 writers on this subject, from Aristotle and Pliny to the time of 

 Bloch and Lacepede, and the author states his belief that the 

 viviparous nature of eels had been inferred from the circum- 

 stance of their being subject to numerous intestinal worms, three 

 species of which are named and described as of frequent occur- 

 rence. 



The sexes are distinct ; the females oviparous. The situation, 



