ASTERIAS. 103 



ing slightly from the origin. The whole surface is of a fine purple colour 

 above, the extremity of the rays yellowish, the under surface tending to 

 that colour also. Plate XX., fig. 1. A narrow channel here running 

 along each ray contains the suckers, fig. 2. The skin appears punctured 

 to the naked eye. Under the microscope it seems covered with a kind 

 of very low tufts or knobs, hardly prominent, rather in circular arrange- 

 ment, interspersed with circular orifices, fig. 3. 



A small hard substance, scarcely prominent above the skin, and gene- 

 rally of a whitish colour, appears towards the edge of the disc of the 

 star-fish of many species. The use of this, called the Madreporiform 

 tubercle, is yet undiscovered. In the present subject it is very small, 

 but the peculiarity of its structure is exposed by the microscope, fig. 4. 



In many of the star-fish also a solid round speck appears at the ex- 

 tremity of each ray, fig. 5, which seems to be composed of several sub- 

 ordinate specks, fig. 6. It is red in the Asterias ocidata, and is seated 

 amidst a few tentacula, extending farther. Some authors consider such 

 specks the eyes of the animal ; Ijut it does not appear that satisfactory 

 .reasons support their opinion, nor can it be shown why the speck may 

 not be a gland instead of an eye. 



This animal feeds on the mussel, but not readily : Probably also on 

 the Lepas. Many reject food entirely. 



In its earlier stages, the Aderias ocidata seems to be of a circular 

 form, followed by development of the rays. Of two minute specimens 

 occuring in the month of July, one was nearly circular, fig. 7 ; originat- 

 ing rays, with some suckers, distinguished the other, fig. 8. After a 

 minute deep reddish orange specimen had been two months in my pos- 

 session, I found it an eighth of an inch in diameter, with five short ob- 

 tuse rays, fig. 9. A small orange specimen, with five stout rays, fed 

 readily on mussel, dwelling long over its prey, fig. 10. 



I advance my opinion of the identity of such small animals as be- 

 longing to the species with reserve, because their history was not followed 

 from its earUest origui. 



The young of the star-fish bears no resemblance to the adult. All 

 its organs are successively developed into form. 



