190 ' ENDEAVOUR " SCIENTIFIC RESULTS. 



The first elytron is sub-circular and bears the long papillae 

 on its anterior edge as well as in the usual position. 



The second is reniform, having a very deep concave exca- 

 vation of its anterior margin, which fits round the first 

 elytrophore. 



So much can be observed with the naked eye ; microscopic 

 examination reveals the fact that amongst the large tubercles 

 and long papillae are smaller tubercles, stellate in form, of 

 various sizes and of various shades of brown and stages of 

 development. Many have a radiate base, or with spines close 

 to the base, from which springs a column, terminating 

 in radiating spines 3-5 in number (PI. xxxviii., figs. 20, 21). 



The long marginal papillae are in reality long inverted cones 

 with a narrow base of attachment and slightly expanded end, 

 which is produced into two or three or more long spines, and 

 the sides also bear spines. In the type they are more 

 numerous and blunt, and resemble the pictures in children's 

 books of an ogre's club. 



The actual margin of the elytron is fringed with delicate 

 hair-like " cilia " around the lateral, posterior, and the outer 

 portion of the anterior margin. 



The gills. The branchial organs are thin- walled, finger- 

 shaped hollow outgrowths of the body-wall, and may be 

 termed " papulae " (a word in common use for similar organs 

 in the Asteroidea). These papulae commence on the third 

 parapodium, where there is a single one on the anterior and 

 on the posterior face, but they soon become more numerous ; 

 then for a few segments before ceasing they decrease in 

 number, and die out after the 23rd segment, which carries 

 the last pair of elytra. 



The arrangement, which may be regarded as normal for 

 this species, as seen at about the middle of the body (PI. 

 xxxix., fig. 25), is as follows : 



On the anterior face of the parapodium there is a row of 

 four papulae, commencing at the "cushion" and sloping 

 downwards along the anterior limit of the upper surface of 

 the foot, the most distal of the row lying close to the base of 

 the notopodium. There is a second row at a lower level, 

 consisting of two (or occasionally three) papulae, of which 

 the distal is the larger and lies below the upper distal papula ; 

 the proximal is removed by some little space from the axilla. 



On the posterior face the arrangement is somewhat 

 different ; there is a row of three commencing at the cushion, 

 and the distal papula is close to the base of the cirrus (in the 



