522 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



cell now degenerates and it is eaten by the clear 

 amoebocytes, which exercise a phagocytic function until 

 the granules make their appearance in them. The 

 granules from the degenerating cells appear to be 

 dissolved by the lymph. 



BESPIKATOBY SYSTEM. 



The branchial cavity is a part of the external world 

 bounded on the inner side by the epimera, and above and 

 on the outer side by a lateral flap of the carapace, which 

 is called the branchiostegite. The gills lie on the 

 epimera. The inflected portion of the carapace is in 

 other higher Crustacea strongly calcified, but in the 

 Pagurids it is always membranous and thin. Conse- 

 quently the gills are far more exposed than is usually 

 the, case. Certain calcified bars serve as some support 

 for this- membranous flap, which is quite free, so that 

 water can enter the branchial chamber from all sides 

 except the roof. The action of the scaphognathite keeps 

 the water in circulation over the gills. 



The branchiae are phyllo-branchiate — that is to say, 

 composed of numerous flat lamellae placed transversely 

 to a central axis. On the inner side of each axis runs 

 the efferent branchial vessel, and on its outer side the 

 afferent branchial vessel. The gills are smaller in front 

 than behind, and they are all pyramidal with their 

 apices pointing upwards. 



All the gills are arthrobranchs but one on the 

 twelfth segment, which is a pleurobranch. No podo- 

 branchs are present. 



The gill formula is the same on both sides, viz. : — 



Segments vi. vii. viii. ix. x. xi. xii. xiii. 

 Arthrobranchs 0222222 

 Pleurobranchs 00000010 



