32 F. G. HEATHCOTE. 



The Heart. 



The heart has been described by Bode, who saw the dorsal 

 vessel dividing into three branches in the head, and also found 

 an artery in the middle of each segment. The dorsal vessel is 

 suspended from the dorsal hypodermis by suspensory muscles, 

 and muscle-fibres connecting it with the fat bodies are attached 

 to its ventral surface. These muscles form a sort of inter- 

 rupted pericardium like that in Julus. 



In each segment of the body there are two pairs of ostia 

 occupying the same position as those in Julus^ but there is 

 only one pair of arteries in the middle of each segment. The 

 heart is composed of three coats, an intima or structureless 

 internal lining, a muscular coat, and a cellular external cover- 

 ing. The layers are not so well marked as in Julus; perhaps 

 this is owing to the small size of the animal. The muscular 

 valvular apparatus of the ostia is the same as that found in 

 Julus (5). The circulation is connected, as in Julus, with the 

 spaces in the fat-bodies. These spaces are often crowded with 

 blood-corpuscles. There is no definite blood-space round the 

 nerve-cord as in Julus. 



The Eyes. 



The shape of the lens is peculiar, and more resembles that 

 of Scutigera (see Grenacher's paper, 3) than that of any other 

 Myriapod with which I am acquainted. Its external surface 

 is highly convex, while the internal is flat. The cells of the 

 hypodermis are continued round the circumference of the lens 

 so as to form a kind of diaphragm. A section through the 

 edge of the lens shows this (fig. 13, h. c). The crystalline 

 cones are arranged in groups, so that a transverse section 

 through the retinal depression gives the appearance shown in 

 fig. 14, J5. I have been unable to find any intrusive connective- 

 cells, but this may be due to want of material. The pigment 

 is thickest at the base of the retina, and also at the commence- 

 ment of the rods (fig. 13, pgt., inner pgt.) . 



