SKELBTO-TROPHIC TISSUES AND COXAL GLANDS. 147 

 7. The cartilage-like capsuligenous connective 



TISSUE OF LiMULUS. 



This is a very remarkable and iiiterestiug variety of connec- 

 tive tissue which occurs in one special organ of Limulus only, 

 and is not found elsewhere in that animal nor in Scorpio. It 

 is described by Gegenbaur as " cartilage " simply, but although 

 agreeing with Vertebrate typical cartilage more closely than 

 does the fibro-massive tissue of the entosteruite, it yet presents 

 some important points of difference from that tissue. 



It occurs in a remarkable pair of ligamentous bands, the 

 entapophysial ligaments which pass from one to another of 

 the dorsal ingrowths of the integument known as the dorsal 

 entapophyses. There is a right and a left series of these 

 hollow chitinous peg-like ingrowths, and a ligamentous band to 

 either series. The ligamentous band is not simply of equal 

 dimensions throughout, but where it is attached to an entapo- 

 physis gives off at right angles a conical knob-like protu- 

 berance. A large series of muscles are attached to these 

 protuberances. 



These ligamentous bands, and their knobs, present in or when 

 cut across a differentiation of substance : we distinguish at once 

 an axial and a cortical tissue. The cortical tissue is identical 

 with the fibroid tissue of the entosternite. The axial tissue is 

 the peculiar capsuligenous tissue now to be described. In 

 PI. XI, fig. 4, the junction of the two tissues is seen. No- 

 where do we find the capsuligenous tissue isolated ; it is always 

 surrounded by a thick coating of the fibroid eutosternal tissue. 

 Occasionally small groups of cells belonging to the capsulige- 

 nous tissue become detached from the axial mass, and may 

 then be seen isolated in a matrix of fibroid tissue. Single cells 

 and groups of cells in various stages of development may be 

 observed in this condition, which enables the observer to de- 

 tect the law of their growth more readily than when the cells 

 are closely pressed together in the large mass of axial tissue. 



The characteristic feature of the capsuligenous tissue consists 

 in the fact that each cell surrounds itself (as in typical carti- 



