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THE POPULAR SCIENCE MONTHLY. 



and, as one of the last was vanishing, the professor imagined that the 

 eye looked back at him with a peculiar and suggestive wink of derision ! 

 The most remarkable representative of the serpent-stars or Oj)hiu- 

 ra7is, as they are called in scientific books, is the " basket-fish," or As- 

 trophyton. The ordinary kinds, as we have seen, have the arms simple • 

 but one genus has the arms extensively branched (Fig. 24). This kind 

 inhabits the deeper waters, and will not be readily obtained except 

 through the aid of dredgers or fishermen, who sometimes bring it up 

 attached to their lines. It attains a diameter of ten or more inches, 

 and the arms go on dividing and subdividing until the divisions are 

 said to number more than 80,000 ! 



If we imagine the Astrophyton with its mouth turned upward, and 



its arms brought near together, and the 

 ab-oral region furnished with a long, 

 jointed, and flexible stem, we shall have 

 a form not very unlike the Pentacrinus 

 cajmt-medusm (Fig. 25), of the West 

 Indies, one of the few survivors of the 

 order of Crinoids that was represented 

 by a great number of species in the pa- 

 Iceozoic ages of the earth's history. 



Some kinds of crinoids, as the rosy 

 feather-star of the European coast, have 

 a stem in the young state, but at length 

 become detached and live as free cri- 

 noids. They thus illustrate, in their em- 

 bryonic stage, the permanent form of 

 the living stemmed species and of those 

 stemmed forms which fill the rocks in 

 many regions, from the Silurian to the 

 Triassic, inclusive. 



It may be remarked here that in no 

 place are fossil crinoids more abundant 

 or varied, and beautiful, than in the sub-carboniferous rocks of this 

 country, especially those in the Mississippi Valley ; although larger 

 species have been found in the Triassic rocks of Europe. 



While the visitor to the sea-shore may hardly hope to secure a living 

 crinoid, it is well to bear in mind that this form is a near ally of the 

 starfishes, serpent-stars, and the Astrophyton, which he can secure. 



It was the remark of one of the old students of Nature that there 

 was nothing on the land that has not its counterpart in the sea. And, 

 if we recall some of the names that have been given to marine forms, 

 we shall see how men have been struck with the resemblances between 

 animals of the land and those of the water. Among fishes Ave have 

 "sea-vampires," "sea-eagles," "sea-wolves," " sea-hounds," "sea-rob- 

 ins," "sea-swallows," "sea-horses," etc. Among mammals we have 

 " sea-elephants," " sea-lions," " sea-bears," " sea-cows," etc. 



Fig. 25.— Crinoid {Pentncrimis caput- 

 medusce), West Indies. 



