of the Fishery Board for Scotland. 



75 



Second Maxilla, 2m., fig. 9, ih. 



The second maxilla is really a maxillipede ; it forms with the maxilli 

 pedes a series of appendages which, in addition to subserving a feeding 

 function, also share the mechanical part of the respiratory process. This 

 is performed by means of the epipodites. 



The epipodite of the second maxilla is the lower half of the scaphog- 

 nathite, while the exopodite is represented by the upper half. 



The division of the second maxilla into joints is difficult to follow. 

 My interpretation of the arrangement is as follows: (1) a basal joint ; 

 (2) immediately above that a bi-lobed joint; (1) and (2) form the 

 protopodite. Above Xo. 2 there is a three-lobed joint, the endopodite. 

 The scaphognathite, which seems to be divided at its middle into two 

 joints, represents in its top half the exopodite, and in its lower half the 

 epipodite. 



There are 81 plumose setae on the margin of the scaphognathite, and 

 four small hairs on the surface. 



On the elongated top lobe of the endopodite the long hairs are 

 sparsely plumose ; they are stiff spine-like hairs, with short, stiff cilia 

 given off in pairs. The tips of the hairs are curved. 



There are 20 hairs on the second lobe ; they also have curved 

 extremities. They are, with three sparsely ciliated exceptions, plain 

 hairs ; one hair only was distinctly serrated on its distal half. 



The third lobe bears 13 hairs on the margin, and two on the under- 

 surface. They resemble those on the second lobe ; only a few are 

 ciliated. 



On the fourth lobe there are stout hairs sparsely furnished with stiff 

 cilia on their proximal halves, and serrations on their distal halves. 

 The fifth lobe, has long, stiff plumose bristles. 



First Maxillipede, \mp., figs. 7, 10, and 23, ih. 



The first maxillipede (fig. 7) has a large first protopodite joint bearing 

 a large epipodite. The upper lobe of the epipodite appears to be seg- 

 mented off. The second protopodite joint is a flattened lobe bearing a 

 large number of serrated spines on its margin (fig. 23). 



The endopodite is two-jointed (fig. 10), and bears several long sparsely 

 plumose bristles. 



Second Maxillipede, 2mp., figs. 29, 14, and 19. 



From the first protopodite joint there arises two processes, united at 

 their bases, one of which is a rudimentary gill, while the other is an 

 epipodite (fig. 14). Both are hollow. An interesting condition was 

 noticed in the gill, which may or may not be constant. The subject was 

 not investigated. In the side of the gill there was a pore opening into 

 a central cavity (fig. 14). The gill is not segmented. Between the 

 wall of this central cavity and the outer wall there is a space which 

 communicates with canals in the protopodite. The hollow of the 

 epipodite communicates with a canal in the protopodite. In the draw- 

 ing the canals are dotted ; the basement tissue is striated. 



The exopodite and endopodite arise from the second protopodite joint 

 (figs. 29 and 19). 



The exopodite, which is furnished with two terminal hairs and a little 

 terminal protuberance, has a long basal joint and a long flagellum in- 

 completely divided by two septa. 



