ISVEHTEHRATES. H7.\7)0ir CROUPS 43 



\'ertpl)rates include the largest, most powerful and most intelli- 

 gent of animals. This group culminates in man, who still 

 Alcove 12 bears A\itness to his chordate ancestry in the retention 



or a es ^^ ^ chorda (cartilaginous spine) , and gill clefts during 

 Including , . ,.,. . , , r , 



Vertebrates embryonic lite. Among these ancestral forms are the 



Ascidians, or Sea-squirts, an enlarged model of which is 



sho^\^^ in the central case, while others are seen among the animals 



on the wharf-piles in the window group. Other models in the central 



case show the development of the egg of typical vertebrates. 



In the circular tower alcove in the southeast corner of the hall 



is a comprehensive synoptic series of stonv corals. 

 Corals ^ ,'.,.'^^ 



Central cases m this tower and at its entrance show 



unusually large specimens, while a magnificent example of madrepore 



coral six feet in diameter is shown to the rear of the bust of Darwin. 



The associations of marine life found in the Bahamas are re])resented 



l)y several small groups in the center of the hall. 



Here also four large models show the mo.squito, which is the 



active agent in the spread of malaria. These models 



°,t^°. represent the insect enlarged seventy-five diameters 

 the IVIalana o ^ 



Mosquito *-*"* ^^ volume four hundred thousand times the natural 



size. The mosquito in its development undergoes a 

 metamorphosis. The model at the left shows the aquatic larval stage; 

 the larvse are the "wrigglers" of our rain-water barrels. The next model 

 is the pupal stage, also aquatic. The third model is of the adult male 

 mosquito, which is harmless, since it never bites man. The fourth 

 model shows the adult female mosquito in the attitude of biting. It 

 is so arranged as to show the internal organs, thus illustrating a tyjiical 

 insect anatomy. In another case is a series of models showing the life 

 cycle of the malaria germ in the blood of man and in the mosquito. 

 In several of the alcove windows are habitat groups of inverte- 

 brates illustrating the natural history of the commoner 



Window 1 i • 1 • I 



and more tvpical animals. 

 Groups 



In the Annulate Alcove is shown the Marine Worm 



Grouj), reproducing these animals with their associates in their natural 

 surroundings, as seen in the harbor of Woods Hole, Mass. The harbor 

 and the distant view of Woods Hole village with the U. S. Fish Com- 

 mission l)uildings are shown in the background, represented by a colored 

 photographic transparency. In the foreground the shallow water of 

 the harbor near the shore is represented in section to 



^ " expose the animal life found on muddy bottoms among 



Group / , „ , , ■ r ■ 



tlie eel-grass as well as the chimneys oi various worm- 

 burrows. In the lower part of the group a section of the sea bottom 



