347 



to the usual four pairs of suckers^ an extra pair was present near the 

 anterior margin, and a more careful examination of the whole specimen 

 revealed yet a sixth pair close to the posterior extremity of the body. 

 These extra pairs were found in other individuals and were seen on 

 whole specimens as well as in sections, I must therefore conclude that 

 the species under discussion constantly possesses six pairs of suckers 

 instead of the four pairs which have hitherto been considered so charac- 

 teristic of all species in which these organs have been noticed. 



The suckers lie very close to the margin of the body, reference to 

 my sketch (fig. 1) will show that four pairs of these are in the usual 



P. 



Figure 1. Myxnstoma costatum Leuck. Ventral view of one of Mr. Crossland's 

 specimens; Actual length 2 mm. P=penis. Pr/ = parapodium. 5' and 5^' = first and 



sixth suckers. 



position, that is to say in the interspaces between the five pairs of para- 

 podia, these are the second to fiftli pairs. The first pair is situated in 

 front of the first pair of parapodia close to the anterior margin of the 

 animal, the last or sixth pair lies a considerable distance behind the 

 fifth pair of parapodia. 



The suckers are all alike and quite typical, haying much the same 



