PjECILOPODA. 
261 
two lateral. The anterior part of the stomach gives origin to two 
large apjjendages, each divided into two branches, Avhich ramify in 
the Avings of the shell. The broAvnish coloured aliment they contain 
renders these ramifications visible. The ceecum is provided near its 
origin with tAVo vermiform appendages. 
The excessive ardour of the males frequently induces them to 
mistake one sex for the other, or to make their advances to pregnant 
or dead females. They are placed in coition on their back, to Avhich 
they cling by means of their feet Avith cups for several hours. The 
period of gestation is from thirteen to nineteen days. The ova are 
smooth, oval, and milk-Avhite. They are fixed Avith gluten on stones 
or other indurated bodies, either in a straight line or in two ranges, 
and from one to four hundred in number ; being pressed against 
each other, their form becomes almost hexagonal. 
TAventy-five days after the extrusion of the ova, and after they 
have assumed a yelloAvish and opaque tinge, the eye and parts of the 
embryo are perceptible. In about ten days more, the shell opens 
longitudinally, and the tadpole issues from it, being at this period 
about three-eighths of a line in length. Its general form is similar 
to that of the adult, but the organs of locomotion present a very 
essential dilference. Muller has described it in this state by the name 
of Arcjulus char on. Four oars or long arms, two sit\iated before the 
eyes and tAVO behind, each terminated by a pennate and flexible pencil 
of hairs that have a simultaneous motion, by Avhich the animal is 
impelled by jerks, project from the anterior extremity of the shell : 
they do not represent the antennse, for they also are Ausible. The 
feet AA'ith cups are replaced by tAvo stout feet, flexed into an elboAv 
near the extremity, and terminated by a strong hook, Avith Avhich it 
clings to Fishes. The only feet proper to the adult, that are deA^eloped 
and free, are those of the second and third pairs, or the tAA^o ambu- 
latory and the tAvo first natatory feet ; the folloAving ones are as yet 
fixed to the abdomen. The heart, proboscis, and ramifications of 
the appendages of the stomach are distinct. After the first change 
of tegument, Avhich is effected by a laceration of its inferior surface, 
the oars disappear, and all the natatory feet are visible. In three 
days more the second change ensues, but without producing any 
important alteration. But after the third, Avhich occurs forty-eight 
hours subsequently to the second, these same feet are converted into 
those Avith cups, still, hoAvever, preserving the terminal hook. At 
the expiration of nine days, there is a ncAv change of skin, and the 
organs of generation, male and female, arc apparent ; another change 
of tegument, however, is required ere the sexes arc fitted for copula- 
tion, so that the period of their metamorphosis extends to twenty-five 
days. Still, hoAvever, they have attained but the half of their proper 
size. For that purpose fresh changes of the tegument, Avhich occur 
every six or seven days, are requisite. Jurine satisfied himself of 
the fact, that propagation ncA'^er ensues Avithout the intervention of 
the male. The females, Avhich he kept separate, perished from a 
disease Avhich AA^as announced by the a])pearance of several Iu’oavu 
glolmles, arranged in a semicircle on the })osterior ])orticn of the 
