364 MR. \V. B. S. BENIIAM ON THE TESTIS OF LIMULTTS. 



represented in his figure of the ovary, so that they occupy but little space between the 

 pericardium and intestine, and the pressure on it would be very slight. The external 

 aperture, both of oviduct and sperm-duct, is similarly situated on the posterior face of the 

 vii. appendage, about one third of the distance from its attachment, near the middle 

 line on each side (as shown in fig. 2). 



The course of the spermatic network. — The sperm-duct rises from the external aperture 

 on the vii. appendage, upwards and outwards, parallel to the "anterior lamellar" 

 muscle of this appendage. It reaches the surface of the liver, through which it runs, 

 just within the muscle attached to the sixth thoracic limb (tig. 1, D 1, D r ). 



Lateral network. — Here it breaks up into three branches ; one runs backwards and 

 outwards, behind this large coxo-tergal muscle, giving off branches, which anastomose 

 with one another, forming a network, which includes in its meshes some of the smaller 

 muscles of the sixth coxa ; the ducts get finer as they recede from the main duct (they are 

 drawn too thick in the figure), and they run to the side and to the posterior corner of 

 the thorax. 



Just after passing the large muscle, an anterior duct is given off, passing along the 

 outer edge of the coxo-tergal muscles, forming a network, which probably runs right away 

 to the front ; but I was unable to follow it further than is represented in the figure, as 

 here the ducts get very fine and easily break. The second main branch from the duct 

 runs inside the coxo-tergal muscles, forwards, giving off networks between the various 

 muscles, some of the smaller ones being included in the rncshes ; these networks pass 

 outwards, and probably anastomose with that on the outer side of the coxo-tergals. 

 However that may be, inside it runs right away in front of the muscles, and on its inner 

 side gives off branches to a median network. 



The median nehcork. — The third principal branch is represented on the right side, and 

 does not appear on the left, so that there is a certain amount of asymmetry. This runs 

 inwards at first, behind the branchio-thoracic muscle, then forwards along its inner border, 

 where it gives off a network across the middle line, lying between the pericardium above 

 and the alimentary tract below. This network {A, fig. 1) was removed, and cleaned, as far 

 as it could be, from liver and connective tissue, and mounted ; it is represented in fig. 3, 

 where A A represent the lateral boundaries ; on the ducts are seen the sperm-sacs, 

 which are usually in groups, one of which opens into the duct, and the others into one 

 another. 



In front of this network is another continuous with it, but separated from it in the 

 figure, owing to the rupture of some of the finer ducts. The anterior lateral boundary of 

 the left side is formed by a duct running from the front of the left branchio-thoracic 

 obliquely forwards to the right side. The network alongside the second coxo-tergal muscle, 

 the most anterior of the large muscles, sends small branches forwards, but not very far, 

 and backwards a larger duct, whence branches and networks pass between the muscles, 

 probably to join a similar lateral network on the right, as was described for the left side. 

 The left border of the median network is formed by two very fine ducts parallel with 

 one another, on the inner side of the branchio-thoracic muscle. These two ducts anas- 

 tomose here and there, and join a network in the abdomen, across the middle line, beneath 



