310 Mr. A. Hancock on a Burrowing Barnacle 



& 6) are of a yellow ochre colour, and the yolk is round and 

 much smaller than the shell ; the yolk gradually assumes an ellip- 

 tical form and soon fills the shell, it afterwards becomes a little 

 flattened on one side (figs. 7 & 8), and by-and-by (figs. 9 & 10) 

 three processes develope themselves from this part ; these pro- 

 cesses are the rudimentary arms : about this time a black spot, 

 the eye, makes its appearance towards one end, and at the other 

 the tail is seen to be forming ; afterwards these parts enlarge and 

 gradually put on their perfect forms, while the egg mass assumes 

 a full rose-colour. 



On examining an individual in which the eggs had been ex- 

 posed, they were all found to be in a high state of development ; 

 on applying a powerful lens, I was delighted to find that nearly 

 all the little creatutes were alive, and most of them struggling 

 for liberty. I soon had the satisfaction to observe several dis- 

 engage themselves, and launch forth into the surrounding fluid — 

 free, natatory Crustaceans. In the course of a few hours nearly 

 the whole were hatched, and the wine-glass in which they were, 

 exhibited a most animated scene. On holding it up to the light 

 they were quite visible to the unassisted eye as white points ; but 

 with the aid of a magnifying-glass their motions could be accu- 

 rately observed, and they were seen to resemble some of the En- 

 tomostraca ; their large, single eye and general conformation show- 

 ing their relationship to the genus Cyclops. They hung as it were 

 suspended in the water, and every now and then dashed rapidly 

 upwards with a fluttering, jerking motion. They commenced 

 their ascent with great abruptness, and as abruptly became qui- 

 escent again ; and once more hanging in the water were seen to 

 descend slowly and gradually with their feet spread out above 

 and their back downwards. They seldom or never moved hori- 

 zontally, their chief object apparently being to ascend either per- 

 pendicularly or diagonally, and always in an inverted position. 



On placing a few of these minute beings (PI. IX. figs. 2, 3 & 4) 

 under the microscope, each was found to be provided with a tail, 

 the body being ovate, broad and depressed, having on the back 

 an ovate shield tapering a little backwards and with a broad in- 

 terrupted line (figs. 2 & 4 a) of bright rose-colour towards the 

 margins : it is to this line chiefly that the general mass of eggs 

 has a rosy hue as they approach maturity. The eye is large and 

 placed in the centre of the forehead ; it is of a very deep rose- 

 colour, — almost black in some lights. The tail is more than half 

 the length of the body, and passes from below the shield, and 

 appears to be composed of two or three articulations : at first it 

 is very stout, but rather suddenly narrowing, tapers gradually to 

 a tolerably fine point and arches upwards ; on the under surface, 

 at the point of contraction, there is a small curved spine. There 



