— 144 — 



all ready to spawn, that this method of investigation may well be dispensed with. Even 

 if a single eel should be found with ripe eggs or running milt in the fishermen's catches, 

 this would tell us nothing concerning where the many millions of silver 

 eels shed their eggs and milt, in other words where the norma! breeding 

 of the eel takes place. 



4. Discovery of the common eel in the open sea. The only eel which has 

 has been taken in North Europe in the neighbourhood of the open sea far from the coasts 

 is mentioned by Calderwood. It was taken on the 27th of December 1892 in the 

 western part of the English Channel 20 miles from the nearest land (Rame Head on 

 the English coast). The specimen was a female 2972 inches long. The description is 

 unfortunately too incomplete to enable us to determine how near the eel was to maturity. 

 Thus, it is remarkable that the size of the eggs is not given. That the specimen was 

 not quite ripe however appears clearly from the description of the inner structure of the 

 egg', and the impression is gained that it was merely a silver eel whose ovary was 

 possibly a little further on in development than usual. The greatest interest attached to 

 this discovery is therefore the locality and period of the year (end of December), both of 

 which seem to show that the specimen was a silver eel on its way out to the open 

 Atlantic, captured before it had reached beyond the English Channel.' 



We may now advance further in the matter by considering the condition of things 

 in the Messina Straits with its deep waters and strong whirlpools. Grassi and Calan- 

 DRUCCio {^'■Riproduzione e metamorfosi delle Anguille", Giornale Italiano di Pesca ed 

 Acquicoltura, No. 7 — 8, 1897, p. 15 — 17) succeeded in obtaining eels there which were 

 quite different from all eels hitherto described. This was due to the action of the whirl- 

 pools in the Messina Straits which bring deep-water animals to the surface, amongst which 

 are various eel species as also specimens of the common freshwater eel {Angitilla vul- 

 garis). These eels are silver eels but further on in development than the silver eels 

 found in shallow water. In outer appearance they differ especially from these by the 

 enormous size of the eyes^ Further they are often somewhat darker than the usual 

 silver eels, and the anterior border of the gill openings especially was in some of an 



I W. L. Calderwood, Note on the Capture of a Fresh water Eel in a Ripe Condition (Annals 

 and Magazine of Nat. History, 6th ser., vol. XII, 1893, p. 35), It is said here: "The ova were appar- 

 ently quite ready to drop from the outer surfaces of the organs (ovaries). Sections showed however, that in 

 each ripening ovum the nuclear membrane was still distinctly visible" (in the Conger according to the author 

 it is gradually dissolved as maturity advances). "The nuclei of largest size were arranged round the periphery, 

 smaller bodies being found amongst the granular protoplasm of the nucleus, The substance of the ovum itself 

 was richly stored with oil-globules, giving the characteristic appearance known in the Conger's egg (CALDER- 

 WOOD, A contribution to our knowledge of the Ovary and Intraovarian Eggs of Teleosteans (Journal M. B. A., 

 vol.11 (N. S.), pi. XII, Fig. 6, 1891 — 92). It may be remarked that Calderwood says nothing whatsoever 

 concerning whether there was anything noteworthy about the external appearance of the specimen of the fresh- 

 water eel described. 



•2 The following measurements are given p. 16. In a male 34^/2 cm. long the diameter (horizontal and 

 vertical) of the eye was almost 9 mm.; in another male (length 331/2) the horizontal diameter was 9, the ver- 

 tical almost 9 mm. In a female of 48'/2 cm. the horizontal diameter of the eyes was a little over 10 mm., 

 vertical 10 mm. — Grassi and Calandruccio explain at the same time, that unusually large eyes also occur 

 in some eels which live in the Roman cloaca, called "chiavicarole". These eels however are not silver but 

 yellow eels and their sexual organs are very little developed. Similar large eyed eels are described by MTntosh 

 .ind Masterman (Brit. Mar. Food-Fishes, p. 450, 1897) as occurring in the pond of the Isle of May. 



