CHAP. IV.] THE VOYAGE HOME. 187 



ambulacral vessek do not correspond with the angles of a reg- 

 uhir pentagon, but with those of an irregular figure in which 

 three angles are approximated beneath and two above. In the 

 female the tentacular feet of the dorsal (bivial) ambulacra are 

 very short ; they are provided with sucking-disks, but the cal- 

 careous support of the suckers is very rudimentary, and the 

 tubular processes are not apparently fitted for locomotion. In 

 the males there is not so great a difference in character between 

 the ambulacra of the trivium and those of the bivium ; but the 

 tentacles of the latter seem to be less fully developed in both 

 sexes, and I have never happened to see an individual of either 

 sex progressing upon, or adhering by, the water-feet of the dor- 

 sal canals. 



In a very large proportion of the females which I examined, 

 young were closely packed in two continuous fringes adhering 

 to the water-feet of the dorsal ambulacra (Fig. 38). The young 

 were in all the later stages of growth, and of all sizes, from 5 up 

 to 40 mm. in length ; but all the young attached to one female 

 appeared to be nearly of the same age and size. Some of the 

 mothers with older families had a most grotesque appearance — 

 their bodies entirely hidden by the couple of rows, of a dozen 

 or so each, of yellow vesicles like ripe yellow plums ranged 

 along their backs, each surmounted by its expanded crown of 

 oral tentacles : in the figure the young are represented about 

 half grown. All the young I examined were miniatures of 

 their parents ; the only marked difference was that in the young 

 the ambulacra of the bivium were quite rudimentary — they 

 were externally represented only by bands of a somewhat 

 darker orange than the rest of the surface, and by lines of low 

 papillae in the young of larger growth ; the radial vessels could 

 be M^ell seen through the transparent body-wall ; the young at- 

 tached themselves by the tentacular feet of the trivial ambula- 

 cra, which are early and fully developed. 



We were too late at the Falklands (January 23d) to see the 



