i 3 o 



THE POPULAR SCIENCE MONTHLY 



the sea here almost like an inland lake, and gives none of the many 

 tide-pools which constitute such an important part of the collecting 

 grounds in our American stations. 



In the two laboratories there are many large and small aquaria, 

 with such an abundant supply of sea-water that animals from a good 

 sized shark to the most delicate coral polyp will live in contentment. 

 The frontispiece from a painting by Fru Astrid Gullstrand represents 

 a corner of one aquarium. The orange colored anemone, like a verit- 

 able flower, unfolds its stinging tentacles to entrap the unwary minute 

 animals swimming by, while below, the eleven-rayed sun-star pulls itself 

 by the contraction of hundreds of adhering sucking tube-feet. With 

 sharp pincers the spider-crab has broken off pieces of algae and hydroid 

 colonies and then planted them among the bristles on its back. Thus 

 the creature is completely masked both from the game it hunts and its 

 own carnivorous foes. The edible mussel spins strong threads from its 

 byssus gland firmly attaching the bluish, or sometimes brownish, shell 

 to the rock or to another mussel. Protectively colored by the olive- 

 green alga around the stem of which his prehensile tail is entwined, 

 Nerophis, the needle-fish, as a model father, broods his young, which 

 are glued fast to his ventral surface during development. 



The Laboratory Pet. 



