434 INVERTEBRATE MORPHOLOOT. 



appendages in these forms, the following table may represent 

 the homologies of the appendages of the two groups. 



Crustacean. Limulus. 



1 segment no appendage no appendage 



3 " antennules " " 



4 " antennae chelicerse 



5 " mandibles 1st pair of legs 



6 " 1st maxillae 2d " " " 



7 " 2d " 3d " « " 



8 " 1st thoracic appendages 4th " " " 



9 " 2d " « 5th " " " 



10 " 3d " " operculum 



LITERATURE. 



A. Gerstaecker. Orusiaeeen. Bronn's Klassen und Ordnungen des Thierreichs, 



Bd. V. 1. Abth., 1866-79. 

 A. S. Packard. T?ie Anatomy, Histology, and Embryology of Limulus poly- 



pliemus. Memoirs Boston Soc. Nat. History, 1880. 

 E. K. Lankester. Limulus an Arachnid. Quarterly Journ. Microscopical 



Science, xxi, 1881. 

 S. Watase. On the Morphology of the Compound Eyes of Arthropods. Studies 



from the Biol. Lab. Jolins Hopkins Univ., iv, 1890. 

 W. Patten. On the Origin of Vertebrates from Arachnids. Quarterly Journ. 



Microscop. Science, xxxi, 1890. 

 J. S. Kingsley. Hie Embryology of Limulus. Journ. of Morphology, vn, 



1893 ; Tin, 1893. 

 W. Patten. On the Morphology and Physiology of tlie Brain and Sense-organs 



of Limulus. Quarterly Journ . Microscop. Science, xxxv, 1893. 



