LIGIA. 91 
by Bruntz (1904), with whose results my observations 
on Ligia oceanica are in agreement. There are four 
kinds of excretory organs, two of which are nephrocytes, 
either grouped or scattered; the third is a definite 
nephridium, or ‘ kidney,’ and the fourth, certain cells in 
the hepatopancreas. 
The maxillary kidneys, or nephridia, occur in the 
basal portion of the second pair of maxillae. They 
consist of two parts —the saccule and labyrinth. The 
saccule is a slightly convoluted tube, which Vejdowsky 
considers is a remnant of the obliterated coelom. It is 
blind at one end, and opens at the other into the labyrinth. 
The cells forming the wall of the saccule are large and of 
excretory nature. The labyrinth communicates with the 
exterior by an aperture at the base of the second maxilla. 
The cephalic nephrocytes are situated at the bases of 
the first antennae. They occur along the ventral and 
lateral sides of the levator muscles of these appendages. 
These cells are fairly large; the protoplasm is homo- 
geneous and contains a number of granules. 
The branchial nephrocytes occur in the abdominal 
region, dorsal to the attachment of the branchiae. There 
are five pairs of groups of branchial nephrocytes. They 
are situated in two lateral lines, each line running above 
the points of attachment of the abdominal appendages, 
and their outer edges reach the bases of the epimeral 
plates. Each group borders on two segments, the first 
group bordering on the last thoracic and first abdominal 
segment. The nephrocytes lie on the sides of the branchio- 
pericardial canal (Pl. IL., fig. 16, br. neph.). They are 
large cells, and the cytoplasm, which is vacuolated, 
contains many granules. Némec considers the branchial 
nephrocytes to be a syncytium, but the cell boundaries 
are very distinct, as Bruntz also noticed. 
