ApRn. 1, 1899.] 



KNOWLEDGE. 



89 



appearance. It has three pairs of appendages, a mouth, 

 and an eye. It is left to its own resources. There are no 

 breasts for it to suck. There is no fostering nurse. There 

 is no education, primary or secondary. It becomes at once 

 a citizen of the ocean. Its business is to moult as qmckly 

 and as often as its growing forces will allow. By successive 

 moultings it comes to assume such a form as that shown 

 in the Nauplius figured by Prof. Chun. Though the 

 animal at this stage is not awe-inspiring by its size, being 

 only about a quarter of an inch long all told, still its 

 lanceolate armour may make it formidable in some social 

 circles, and the glassy transparence of its caparison invests 

 it with beauty. 



Nauplius of Lepas anatifera, 

 sliortly before hatching. 

 From Groom. 



Nauplius of Lepas, sp., 

 just prior to the Cypris 

 stage. From Chun. 



Mr. Theodore Groom i considers that the movements of 

 the Nauplius are brought about exclusively by the activity 

 of the three pairs of appendages, propelling it by a series 

 of jerks. These follow one another with great rapidity in 

 the newly hatched Nauplii, but more slowly afterwards. 

 Nature in some way teaches them to husband their re- 

 sources, and that the business of hfe should be conducted 

 ohne Hast ohne Hast. By this policy, some of them, it is 

 calculated, after the first moult can swim something over 

 two inches in a minute, about a hundred times their own 

 length, equivalent to a mile in eight minutes for a man six 

 feet long. Whether swift or slow, their movements are 

 probably not for any swimming competition nor for the 



* Die Nauplien der Lepaden. 

 1895. 



t '• On the Early Development of Cirripedia." 

 Groom, b.sc. Phi'l. Trans. S. S.. 1894. 



Carl Chun. Sibliotheca Zoologiea, 



By Theodore T. 



mere fun of the thing. Their throat is said to undergo 

 continuous contraction and dilatation by means of the 

 muscles with which it is furnished, and to constitute a 

 suction pump which causes an intermittent stream of water 

 to enter the mouth. At the same time "the powerful 

 strokes of the three pairs of appendages sweep backwards 

 and inwards any small organisms or particles entangled 

 between the network of hairs and bristles." Mr. Groom 

 seems to have taken a mean advantage of their innocent 

 rapacity, to judge by the following paragraph of his 

 essay : — 



" Though the Nauplii of Balanus, Chthamalus, and Lepas 

 refused to eat starch, they greedily took up water con- 

 taining carmine, indigo-carmine, methyl-blue, litmus, etc. 

 In the case of the first three substances, considerable 

 accumulations were formed after a short time in the 

 stomach and intestine, but the greater part of the carmine 

 was passed out unabsorbed." 



Theyoimg that are born must be inconceivably numerous. 

 The dangers of their childhood are also innumerable. By 

 dint, however, of energetic feeding and refusing to eat 

 starch, a vast remnant of the Nauplii pass into the Cypris 

 stage. This transformation derives its name from the 

 surface resemblance which the Cirripede undergoing it 

 assumes to the genus Cypris, among the Ostracoda or Box- 

 Crustacea, discussed in 

 the last chapter. The 

 soft parts and appen- 

 dages of the organism 

 are now almost entirely 

 enclosed in a pair of 

 valves comparable to 

 those of a minute 

 mussel, with the in- 

 significant appearance 

 of a Little brown ovate 

 seed. But if we look 

 after the inward parts 



of them, we shall find them not at all like those of 

 a mollusc. They are now approaching the character of 

 the adult form. The animal will before long settle down 

 in life, and form a permanent attachment. There is no 

 romantic love-making concerned in this ; the attachment 

 in question is a local affixing. By means of cement-glands 

 the head is attached to any suitable object, and the legs 

 thrown upward, or, if not upward, at least in a direction 

 opposite to the foothold which is monopolized by the head. 

 There is no clownishness or dramatic vulgarity in this 

 eccentric behaviour of the legs, since these many-jointed 

 and beautifully plumose limbs (the cirripeds or ringlet- 

 feet) are encased within a variety of plates or valves, from 

 which they only protrude when occasion demands, with 

 coy reserve. 



In Lipas, and various other genera of the pedunculate 

 or stalked barnacles, the valves are reduced to five, a 

 manageable number for purposes of explanation. The 

 narrow curved valve on the left, in the figure given 

 above of an adult Lejias anatitera, is called the carina, 

 or keel, from its shape. It is impaired. At the top of the 

 figure is seen one of a pair of valves called terga or 

 back-plates, and below this on the right, one of a pair 

 called scuta or shields. In Scalpellum there are from 

 twelve to fifteen valves, and the peduncle is covered with 

 scales. Nevertheless, the five primary valves above 

 mentioned maintain a predominance. In the old genus 

 Pollicipes, which was already flourishing in the Lower 



* The specimen having been treated with caustic potash, and so 

 rendered transparent. 



Cypris-stage of Lepas australis.* 

 From Darwin. 



