50 EMBRYOLOGY OF THE STARFISH. 



tion ; but the odd tentacle is always curved upward, and carried between 

 the two middle spines of the extremity of the rays. When we see the 

 Starfish in profile (PL VII. Fig. 2), the red eye-siieck appears prominent 

 near the edge of the diskj surmounted by the upturned tentacle {f t'), 

 of a slight rosy hue. This manner of carrying the terminal tentacle re- 

 minds us strongly of the way in which ^Eginopsis, as well as the young 

 of so many of our Hydroid Medusse, carry their marginal tentacles : Ne- 

 mopsis, Staurophora, Turritopsis, Willia. 



This is the most advanced stage of the young Starfishes (PI. VI. Fig. 

 11) which I have succeeded in raising in confinement. When we com- 

 pare this with an adult, having long, slender-pointed rays, four rows of 

 suckers, its surface covered with pedicellariae and water-tubes, surround- 

 ing individual spines, like so many wreaths, we cannot foil to be struck 

 with the astonishing changes of form which must still take place to bring 

 this pentagonal star to any shape resembling a slender five-rayed Star- 

 fish. In foct, when we remember how rarely embryologists continue the 

 study of the egg beyond the moment of hatching of the embryo, it is 

 not to be wondered at that this same young Starfish should be intro- 

 duced to us again and again, in its different stages of growth, under half 

 a dozen new names, both generic and specific. It is only by a thorough 

 knowledge of all the changes of form through which these young em- 

 bryos pass, from the first moment of their existence till they are full- 

 grown, that we can hope to remedy this evil. 



The next state of our young Starfish is, when magnified (PI. VIII. 

 Fig. 1), even more different from the adult than the pentagonal state 

 of PI. VI. Fig. 11. The young Starfishes figured on this Plate (PI. 

 VIII.) were all found attached to roots of Larainaria, thrown up on 

 the beaches, in the neighborhood, after a storm ; and from their differ- 

 ent stages of growth, as compared with the oldest Starfish raised from 

 a Brachiolaria (PI. VI. Fig. 11), specimens of which were also found 

 upon these roots, it is probable that the sizes here figured are one {Fig. 

 1), two {Fig. 8), and three {Fig. 10) years old. A considerable number 

 of specimens were picked up in this way, and they could all be arranged 

 into very distinct groups, representing the Starfishes of the present and 

 of two previous seasons. There seemed to be no gradation from one 

 group to another, such as we have among the young Sea-urchins, which, 

 in consequence of their manner of breeding during the whole year, form 



