318 



isticalh' diamond shaped, and their yellow color is very marked. They can be seen in 

 both the living organism and in celloidin sections. Their color and shape are suggestive 

 of crystals of uric acid. 



These crystals do not appear to be identical with the inorganic granular mass 

 occurring in the reticular connective tissue of the pericardium. This mass is of a highly 

 refractile substance and can be seen through the dorsal body wall. It occurs in both 

 male and female animals (fig. 131), even in the very young organisms and those still 

 within the brood-pouch. This granular mass is well shown in the photograph of the 

 young organisms in figure 124 and in the drawing (fig. 125). In outline it is roughly 

 the shape of the letter H. It has been observed in animals which have been starved 

 for a period of a month, so that it is not to be considered as reserve food stuff. Its 

 function is not known. 



Fig. 131. Limnoria lignorum, photographed alive in position in burrows. X -i. 



The reproductive organs in the female consist of two large ovaries (ovar., fig. 129) 

 and the paired oviducts. There is also a small sac-like organ {ace. o., fig. 129) connected 

 with the posterior end of the ovary. It contains some loosely arranged cells with 

 irregular or pointed margins. Since it does not appear to be a seminal receptacle, it 

 is possible that these cells are nurse cells and that the connecting strand with the 

 posterior end of the ovary forms a nutritive channel. The eggs with the greatest accu- 



