AND THE MALES OF CERTAIN CEPHALOPODS. 133 



II. Anatomy. 



We shall first treat of the anatomy of the male, whose orga- 

 nization in general does not differ, in fact, from that of other Ce- 

 phalopods. The ventral region of the mantle is provided with a 

 very complicated constrictor apparatus, fixed to the fibrous mem- 

 brane which invests the intestine. After having cleft the mantle 

 longitudinally (PI. II. fig. 1.), we observe the branchiae, each with a 

 branchial heart situated at its base, and not differing in structure 

 from those of other Octopods. During life, however, these 

 branchiae exhibited great contractility, and the branchial hearts, 

 whose function has been questioned, pulsated regularly. The 

 fibrous membrane which invests all the intestines is covered, 

 especially below, with numerous chromatophora, which contract 

 and dilate alternately. We see across this membrane the vaguely 

 marked contour of the last portion of the intestine, of the ink- 

 bag and of the genitalia which occupy the posterior portion of 

 the body. The conjoint aperture of the rectum and of the ink- 

 bag is placed upon a little muscular tongue which ends forwards 

 in two very fine points, and which passes so far forwards below 

 the funnel that the posterior edge of the latter covers it com- 

 pletely. At first we sought in vain for a long time for the aper- 

 ture of the generative organs, which is perceived with great dif- 

 ficulty, when an accident discovered its position. One of the 

 specimens which we were examining presented through the 

 mantle a streak of white matter which began to fill the branchial 

 cavity. Having carefully opened this individual, we saw a coil 

 of the seminal thread, which we shall describe by- and- by, escape 

 from a semilunar aperture upon the left side, by the side of the 

 place where the branchial vessels leave the intestinal sac to pass 

 into the branchia. It was afterwards easy to perceive this very 

 much contracted cleft in all specimens, and to convince ourselves, 

 by examining the internal generative organs, that this asymme- 

 trical orifice was the sole means of discharging the contents of 

 the generative organs into the branchial cavity. 



After having taken away the fibrous intestinal sac (PI. II. fig. 1.) 

 we easily discover the rectum, which is very delicate, passes 

 from below upwards from the dilatation of the large trunk, and 

 which rises among a considerable mass of venous appendages 



