I20 



PATTEN AND REDENBAUGH. 



[Vol. XVI. 



dite, and by a small extensor {e!") arising from the posterior side 

 of the propodite and inserted upon the posterior proximal margin 

 of the dactylopodite. These muscles close and open the chela. 

 A small flexor muscle (/.'") is found at the base of the inner 

 mandible. This muscle is absent in the second appendage. 



i.m 



Fig. 4. — Diagram showing the muscles and nerves of the chilaria of Limul us, from anterior side. 

 The appendages are revolved outward about 45° (magnified nearly i^ diameters). 



b.cP, capsuliginous bar or branchial cartilage; emio., endocranium ; k.c, haemal side of 

 carapace; ht., heart; hit., intestine; oc.r., occipital ring; p.s., pericardial sinus. 



Muscles: 7^~^, plastro-coxal muscles; 7'" and g, tergo-coxal muscles; /.;«., inter-tergal 

 muscles; v.p.mJ, veno-pericardlac muscles. 



Nerves : h.nP and ^, haemal nerves of chilarial and opercular neuromeres ; i.ii.T , intestinal 

 nerve ; in.nJ and ^, integumentary branches of haemal nerves of chilarial and opercular seg- 

 ments ; l.CM., lateral cardiac nerve; l.s.n., lateral sympathetic nerve; in.c.71., median cardiac 

 nerve; «.«.7 and *, neural nerves of chilarial and opercular neuromeres; /., pericardium; 

 j.c.«.7and', fused segmental cardiac nerves of chilarial and opercular neuromeres. 



TJie Muscles of the Sixth Appendage (Text-fig. 3). — These 

 are similar to the muscles of the second, third, fourth, and fifth 

 appendages, except those which move the joints beyond the 

 propodite. A large muscle (_/".^), arising from the posterior, 



