THE MUSEUM. 



21 



Arcliaster Agassizi [fig. 2 J from the 

 Massachusetts coast, is a deep sea form 

 but quite interesting. It is found from 

 50 to 2,000 fathoms and measures 

 three or four inches across. It is of a 

 cream}' buff color. Closely allied to 

 this is Archiastcr Aiiicricanus from 

 same locality but usually found in wat- 

 er from 75 to 125 fathoms. 



Asterias viilgaris [fig. 3] of the N. J. 

 coast is a very common species. In fact 

 this species with Asterias berylintis 

 of the Massachusetts coast and 

 Asterias Forbcsii, a very small species 

 of Narragansett Bay, are found in great 

 numbers in their respective quarters. 

 A. berylinns is found from Halifax to 

 Florida, while yi. 77//^^rr/\9 ranges from 

 Long Island sound to Florida, both be- 

 ing common in Massachusetts bay. It 

 is very interesting to watch their move- 

 ments, and I shall dwell to some ex- 

 tent on these species, as doubtless the 

 largest number of people in the U. S. 

 are familiar with them. From under 

 the surface of the arms, at whose union 



is situated the central mouth, a great 

 number of delicate tubules, each one 

 terminated by a minute sucking-disk, 

 ^may be seen to be vigorousl}' in motion 

 the whole series undulating like wind 

 swept grain. These tubules are hollow 

 and fed from within with sea water, 

 the increase diminution of which within 

 the tubules, regulated by the will of 

 the animal, determines the length to 

 which they may be extended or pro- 

 truded. Attaching themselves to for- 

 eign objects by means of their sucking- 

 disks, the animal may in this way be 

 either drawn forward, or the object of 

 its search drawn to it. The system of 

 vessels that supplies the tubules with 

 water, governing as it does the walking 

 apparatus of the tube-feet, is known as 

 the "Ambulacral" system spoken of 

 heretofore. The area, again, along: 

 ^^hich the tube-feet are placed, has 

 been called the "Ambulacral Zone" 

 and the intermediate spaces, — the 

 sides and backs of the arms,-— the inter- 

 ambulicral. On the back of the ani- 

 mal, a little sub-central, and in the 

 angle between two of the arms, is a 

 tumid little body, of a bright orange 

 color, called the "Madreporic tuber- 

 cle" through which the sea water 

 gains access to the ambulacral system 

 of vessels. All species of Star-fishes, 

 but this one especially, are voracious 

 animals, and they have a- method of 

 securing their food which is at once 

 novel and to say the least effective. 

 Siezing their prey which consists large- 

 ly of shell-fish, they arch themselves 

 over it, turn their stomachs inside out, 

 so as to completely envelope the deli- 

 cate morsel, and then deliberately pro- 

 ceed to make a meal. In fact, on 

 some parts of our coast, as Mar\land. 



