346 LIVERPOOL MARINE BIOLOGY COMMITTEE REPORT. 



quadrate, and have a dark belt along their anterior margin, 

 are attached to the dorsal surface of the body on every fourth 

 segment (see PL VII, fig. 6). Every elytron-bearing segment 

 possesses two protuberances, rounded or quadrate on surface 

 (PI. VII, fig. 6, d), and each forming a low column, about 

 tV in. high. The surface of the protuberance is attached to a 

 depression in the under surface of the scale to the left (or 

 right, for the right-hand scales of the middle line). The 

 segments which bear the elytra have no dorsal cirri. The 

 non-elytron-bearing segments have cirri (PI. VII, fig. 6, a), 

 but they have also protuberances identical in position, but 

 not in form, with the elytron-bearing protuberances. Both 

 segments intervening between two elytron-bearing segments 

 have similar protuberances (PL VII, fig. 6, b, c). Each of 

 these is a short column, oval in section, having its long 

 axis at right angles to the long axis of the body, and having 

 its internal and external angles produced into horns. These 

 horns on their ventral sufaces, and a considerable portion of 

 the columns, are covered by ciliated epithelium (see PL VII, 

 fig. 3), which probably fulfils a branchial function. The 

 scales are arranged so that the left-hand scale overlies the 

 right-hand one. Their posterior margins are inserted between 

 the two branchial protuberances, overlying the anterior and 

 underlying the posterior of these. The dorsal cirri, as stated 

 by Mcintosh, are perfectly smooth (PL VII, fig. 6, a). The 

 bristles are described and figured by Mcintosh {loc. cit.). 



In transverse section the attachment of muscles to the 

 elytron -bearing protuberance is seen (PL VII, fig. 1). Two 

 pseudhaemal vessels appear one above the alimentary canal, 

 between the two masses of the dorsal muscles, the other 

 beneath the alimentary canal, and lying in connection with 

 the reproductive follicles and immediately above it. The 

 vessels are not lined by epithelium, and are probably simply 

 portions of the coelome cut off". The outer wall of the 



