160 PROFESSOR E. RA.Y LANKESTER. 



forming one system, and it is these irregular spaces which are 

 lined by the glandular corticated epithelium. In a section 

 seen with a low power, these passages (cseca) present the 

 appearance shown by the white spaces in Plate XI, fig. 5, but 

 it must be remembered that in a thickish section the passages 

 are seen to bend and twist, anastomosing with one another, and 

 leaving broad solid trabeculae between them. 



The centre of each lobe of the coxal gland of Limulus 

 (woodcut, fig. 3, c) is occupied by a blood-vessel, around which 

 the lacuniferous connective tissue is disposed in concentric 

 layers, into which tissue a few out-growths of the csecal 

 system (the subdivided gland-lumen) push their way. As we 

 recede from the axis of the lobe the glandular spaces become 

 more abundant and the substance therefore spongey, until 

 again at the periphery the glandular spaces cease, and the 

 compact form of connective tissue (PI. X, fig. 1 ; i) clothes the 

 surface of the lobe and passes over rapidly into the form of 

 normal lacunar tissue (see PI. X, fig. 1 ; h) . 



The intercsecal connective tissue is far more abundant 

 in Limulus than it is in Scorpion : it resembles that of the 

 latter far more closely than it does the colloid tissue of 

 Mygale. It is clearly enough only a local modification of the 

 " lacunar tissue " which packs the cseca of the gastric gland. 

 Its lacunar spaces are often large, but the protoplasmic cor- 

 puscles which often closely line those of normal lacunar tissue, 

 are here more sparsely developed. The skeletal element also 

 presents a distinct character. It tends to develop long fibre- 

 like cords of a highly refringent character which must give a 

 certain strength and elasticity to the framework of the gland 

 (see PI. XII, fig. 4; b). There is no direct transition from 

 this intercsecal tissue to the lacunar tissue, the periphery of 

 each lobe being, as above pointed out, formed by a special 

 variety of connective tissue in which the skeletal element is 

 almost entirely absent, and the protoplasmic bodies are set 

 closely in a compact mass (PI. X, fig. 1 ; i). 



Packard has already drawn attention to the red colour of the 

 coxal glands of Limulus in the fresh state. This colour led 



