42 



corpuscles of 15 /* diameter (PI. VI, fig. 44), with rounded 

 or slightly curved nuclei. After a lapse of several 

 minutes, these corpuscles are seen — if the blood is placed 

 in a watch-glass after withdrawal from the body — to 

 congregate together in large clusters. 



(2) A liquid medium, in which the above corpuscles 

 float, containing: — (1) Mineral salts (including iron in 

 small quantity, Grirod) ; (2) slight traces of organic 

 compounds ; and (3) 9 per cent, of the substance 

 Haemocyanin, an albuminous compound containing 

 copper. According to Cuenot, it is the great quantity of 

 copper present which gives the blue tinge to the blood. 

 This darkens when exposed to air, because of the oxidation 

 of the copper. The blood of Eledone, like that of all 

 Cephalopods, contains no fibrin. The analysis of the 

 contents of the blood plasma has not been made for 

 E. cirrosa, but Fredericq and Cuenot made it for Octopus 

 and Sepia respectively. Two glands have been suggested 

 as the seat of origin of the blood corpuscles : — (1) The 

 branchial gland (Joubin), and (2) the white body 

 ( Kaussek). 



Heart. 



In Eledone the heart is situated just behind and to 

 the right of the stomach (PI. VI, fig. 42, V.). It is, 

 however, rather ventral to this organ, but dorsal to, and 

 therefore concealed by, the kidneys 



The heart is rather smaller than the stomach, and 

 consists of three chambers, two auricles and a central 

 ventricle, into which the auricles open laterally, one a I 

 each side. The two auricles are essentially the dilated 

 and slightly muscular basal portions of the efferent 

 branchial vessels, and may be defined as the portion of 

 these vessels lying between the posterior end of the gill 

 and the ventricle (fig. 42, au.). The auricles are 

 symmetrical, but the thicker vailed, more fleshy ventricle 



