Io8 CALIFORNIA ACADEMY OF SCIENCES, [Proc. 3D Ser. 



Lymphocytes. — (figs, no, in.) The lymph of the 

 coelojnic cavity contains numerous lymphocytes of various 

 kinds, but principally amoebocytes. The lymph exuded 

 from the irritated animals consists almost exclusively of 

 amoebocytes and a few eosinophile cells. 



The amoebocytes are of different sizes and forms, some 

 being perfectly round and showing no pseudopodia, while 

 others show numerous examples of such amoeboid projec- 

 tions. Between these two extremes there are numerous 

 intermediate gradations. One of the most extreme forms 

 is figured at G., fig. no. The pseudopodia may be broad 

 or pointed, many or few. The cytoplasm shows in places 

 a branching or foaming structure (Z^) with concentrations 

 of greater density in the longer arms. The archosome 

 (Eisen 20) is more or less well defined and shows at least 

 two concentrically arranged zones, one exterior to the 

 other. The interior zone stains darker, and may, perhaps, 

 be composed of centrosomes. The archosome is often 

 surrounded by a denser granulated cytoplasm which is 

 probably homologous with the granosphere. In double 

 staining with eosin and methylen-blue, the archosome with 

 the granosphere stains distinctly red, while the balance of 

 the cell stains blue. The nucleus varies in shape and is 

 either rounded and even, or polymorphous, as in leucocytes; 

 but as there are intermediate forms, I conclude that all 

 belong to the same class of lymphocytes. 



Eosinophiles. — These are found in limited number; they 

 are smaller than the amoebocytes, round, globular, without 

 any amoeboid projections, and their cytoplasm is composed 

 of numerous intensely staining globules of erythrophile 

 nature. The diameter of the eosinophile granules is about 

 one-twentieth that of the cell itself. The nucleus of the 

 eosinophile cell is much smaller than that of the amoebocyte. 



Microcytes. — (fig. 117.) This name is proposed for very 

 minute, non-nucleated bodies occurring in large numbers in 

 the lymph, scattered among the lymphocytes. These bodies 

 are oval in shape, pointed at both ends, and of different 



