ART. 7. STUDIES OX LARVAE OF CKABS HYMAN. 7 



prominent shoulder at the point where they meet the hepatic areas. A row of small 

 irregularly disposed spines on the sides of the carapace. The second and third pairs 

 of maxillipeds (figs. 70 and 71) have the same structvire as in adult Pinnixae, the ter- 

 minal segment of the inner limb lieing articulated with the penultimate segment near 

 the proximal end of the latter, in such fashion as to form a sort of didactyle claw. 



The chelae are didactyle, the dactylus closing against a long process of the ante- 

 cedent segment. The following pairs of ambulatory appendages are extremely long, 

 the last pair being much smaller than the rest, as in the adults of this genus. 



The abdomen is small, closely folded against the sternum, and is not used as a swim- 

 ming organ. It carries foiu- pairs of appendages (fig. 65), which consist of a basal seg- 

 ment which supports two branches. The outer branch is much larger than the inner, 

 and bears about nine setae on its border. The telson is broader than long, its posterior 

 margin regularly convex and fringed with setae. 



Blotches of dark pigment, of dendritic forms, occur on the carapace, sternum, and 

 abdomen, arranged as represented in Figm'es 63 and 64. 



BIBLIOGRAPHY. 



Bell, Thomas. A history of the British Stalk-eyed Crustacea, pp. 1-386, 174 text 

 figures ("wood engra^'ings"), London, 1853. 



BiRGE, E. A. General notes, zoology. Prof. E. A. Birge on the first zoea stage of 

 Pinnotheres ostreum, American Naturalist, vol. 16, pp. 589-591, text figs. 1-11, 

 Philadelphia. 1882. 



Faxon, Walter. On some young stages in the development of Hippa, Porcelana, 

 and Pinnixa. Bull. Mus. Comp. Zool., vol. 5, no. 11, pp. 253-268, pis. 1-5, Cam- 

 bridge, 1879. 



GouRRET, P. Considerations siu- la faune pelagique du Golfe de Marseille. Ann. 

 Mus. Hist. Nat. Marseille, ZooL, vol. 2, mem. 2, pt. 1, pp. 14-24, pis. 1, 2, Mar- 

 seille, 1882. 



MiJLLER, Fritz. Fiir Darwin, only the English translation by W. S. Dallas seen: 

 Facts and arguments for Darwin by Fritz Miiller with additions by the author, 

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Rathbun, M. J. The Grapsoid Crabs of America. Bull. U. S. Nat. Mus., no. 97, 

 pp. 1-461, pis. 1-161, text figs. 1-172, AVashington, 1917. 



Semper, Carl. Animal life as affected by the natiu-al conditions of existence, pp. 

 .1-472, text figs. 1-106, 2 maps, London and New York, 1881. 



Smith, S. I. On the species of Pinnixa inhabiting the New England coast, with re- 

 marks on their early stages. Trans. Conn. Acad. Sci., vol. 4, pp. 247-353, New 

 Haven, 1880. 



Thompson, J. V. Memoir on the metamorphosis and natiu-al history of the Pin- 

 notheres, or Pea Crabs. Entomological Magazine, vol. 3, art. 6, pp. 85-90, text 

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