The Chitons. Coat-of-Mail Shells 



assembJed here, including some bf the largest and most brilliantly 

 coloured forms. 



The Showy Chiton (I schnochiton conspicuus, Cpr.) is a large 

 and beautiful chiton found from Santa Barbara to Magdalena Bay 

 It is three to four inches long, the shell shaded green, and finely 

 .granulated, pink at the umbo of each valve, and smooth. Faint 

 wavy bands sculpture the lateral areas; the girdle is narrow, 

 and coated with bristles set so close as to form a velvety cover. 

 The front valve is concave. 



The Gray Chiton (/. Magdalenensis, Hds.), a smaller species 

 , with much the same range, is also found at Santa Catalina and 

 Santa Barbara Islands. It is pale green underlaid with pink, 

 and mottled, with radiating riblets, and the central areas have 

 small diamond-shaped pits. The first valve is flattened, not 

 concave, in front. The girdle is covered with fine, close scales. 

 The foot projects forward, covering the head. 



In studying the development of this species Heath found 

 that the eggs were laid in gelatinous strings almost a yard in 

 length, the average number of eggs contained in each string 

 being 1 1 5,940. When six days old the young chitons enter upon 

 the free-swimming period of their existence. This lasts but two 

 hours. After it is spent, they settle down upon rocks or seaweed 

 and undergo a gradual metamorphosis. 



During all the stages of development passed up to the time 

 of settling down the chiton exhibits radial instead of bilateral sym- 

 metry The embryology of Annelid worms is similar. This seems 

 to point back toward a common ancestor of these two groups. 



The Magnificent Chiton {Chiton magnificus, Desh.) has a 

 very large black shell, with minute blue dots scattered over it, and 

 a blue lining. The surface of the back is smooth, with faint radiat- 

 ing lines. The girdle is narrow, made of shiny overlapping black 

 scales. This handsome, smooth-shelled chiton attains the length 

 of four or five inches, with a breadth of three inches. 



Habitat.— Chilian coast. 



C. Goodallii, Brod., is a large smooth chiton, often fully 

 six inches long, with straight sides sloping up to a central 

 peak, like the roof of a house. The colour is dark brown, the" 

 narrow girdle paler brown, made of flat overlapping scales. The 

 lateral areas of the middle six valves are crossed by dark con- 

 centric bands or terraces. These indicate rest stations at which 



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