172 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



we lUiiy tf-rin it. extends from the iinterioi- portion of the pallio-visceral ligament upward ;ind 

 backward to the liody wall just above the origin of the siphon. Thus the testis, a speeialized 

 portion of the wall of the genital ligament, comes to be slung by its upper and lower ends. 



The upper attachment of the testis is effected b.y a membranous ligament about 2 centimeters 

 broad extending from the anterior face of the testis, 1 centimeter Itelow the upper end of th(> 

 organ, to the Iwdy wall just above the origin of the siphunclc The attachment of the ligament 

 to the body wall is diagonal, passing across the body from right to left, and also somewhat down- 

 ward. In this way the opening of the siphuncle into the c(jelom comes to lie upon the right side 

 of the genital ligament. Tissues of the base of the siphuncle seem to extend into the genital 

 ligament, so that there is always a bulge in the ligament at this point. 



Being continued on the testis the ligament separates into two portions which run downward 

 over the anterior surface of the organ. These are merely elevations of the tunic of the testis. 

 One passes over the surface of the testis to the left, leaving it at its edge and forming the sus- 

 pensory ligament of the stomach (gas. 1.). The other passes downward, first to the right, then 

 slightly to the left until it reaches the anterior edge of the testis, where it is continued as a dorsal 

 fold of the pallio-visceral ligament over the heart. This forms the suspensory ligament of the 

 intestine and rectum (1. 1.). It is attac-hed first to the portion of the intestine leading forward to 

 the rectum: enveloping this it forms the mesenter^y between the liranchesof the intestine, and then 

 envelops the hackwardly dii-ected branch of the intestine. It must be remembered that all these 

 ligaments are double folds, in some of whii'h the walls covered externally by the ccelomic epithe- 

 lium are closely pressed together, while in others organs or portions of organs, such as the intes- 

 tine, stomach, etc., are pushed between the walls. 



The posterior side of the anterior end of the testis is l)roadly attached to the pallio-visceral 

 ligament. This attachment is immediately posterior to the heart. As the heai't is surrounded 

 and slung by the same ligament, the ventral surface of the testis and the dorsal surface of th(> 

 heart come into very close contact. 



The funnel-shaped tube through which the cavity of the testis is ])laced in conmnuiicatidu 

 with the vas deferens is formed by a thickened portion of its tunic aliout 4 millimeters in lengtii 

 and 3 millimeters in breadth at the tip. The tip is sometimes slightly expanded. The opening 

 in it is slit-like. 



The surface of the testis inside the tunic appears somewhat granular. Kekr, describing 

 the striicturt' of the testis of an immature individual, says that "the apei'ture of the organ is seen 

 to lead into a vestit)ule, into which t)pen several ducts. Each of these, traced inward, divides up 

 into numerous tubules which end blindly and are aggregated into distinct lobes and lobules. 

 Vestibule and tubes are lined by epithelium continuous with that of the general coi'lom.'" 



The measurements of the testis of one specimen were: Length. 41 millimeters; breadth, ?)ii 

 millimeters; thickness, 24 millimeters. At the right of the t(\stis. and extending anterior to it, 

 is a large accessory gland, which is formed around the convoluted vas deferens (ac. gl.). The 

 accessory gland lies within the pallio-visceral ligament upon the right of the right anterior 

 viscero-pericardial aperture. Posteriorly it projects freely, carrying the dorsal wall of the 

 ligament over its surface. Lying in the pallio-visceral ligament in this way. the accessory gland 

 is very closely attached by the ligament to the anterior portion of the testis. On account of the 

 elevation of the post(M-ior portion of the accessory gland above the pallio-visceral ligament, the 

 poi'tion of the ligament uniting this portion of the gland and the testis appears at first sight like 

 a separate ligament, but is in reality only a fold of th(> pallio-visceral ligament (y). 



The accessory gland projects entirely dorsally fiom the pallio-visceral ligament. It forms 

 an oval organ, smaller anteriorly than postiM'iorlv, the measurements of which are: Length, 27 

 millimeters; breadth, 20 millimeters; thickness, 15 millimeters. Its tissues are uuich firmer 

 than those of the testis. 



When in its natural position the accessory gland lies against the right anterior face of the 

 testis, the loop of the intestine t)eing held between the upper portion of the gland and the testis. 

 In Fig. 38 the gland is turned outward so as to show the face which is ordinarily pressed against 



