rilYM"!.' UIKS. 



D. 17. ScyUariu arctns, with th- nervous system exposed. The 



markable for its relatively large BUM : 



i, .. -I,,, usual ncrvi- to the cephalic sense-organs, 



l.ui ihr optic truct> and ganglia, owing to the great 1)r( ' a(Itl1 

 of the hracl, are peculiarly long and slender. The suh- 

 CMOphag''! and thoracic ganglia are longitudinally 

 apppn.ximaled, hut (with the exception of the components 

 the subcesophageal ganglion) an' not fused together. 

 Between the 2nd and ;>rd and :ird and 4th thoracic ganglia 

 the connectives are quite >eparate, leaving in the latter 

 |Hiii"ii a large opening between them for the passage of 

 tin- sternal artery; elsewhere they are bound together by a 

 nmiiioit netiri lemma-sheath. The last thoracic ganglion 

 injected with a chain of six scgmentally placed 

 alNlominal ganglia. They nrc iran.-versdy concentrated. 

 ..nd an- eomi' < b d t..g.-ther by an a|parently single cord. 

 the. result of the tran-ver>e concentration of the jaired 



Bouvier, Ann. Sci. Nat, ser. 7, t. vii. 1889, p. 7,'i. 



D. 18. Th- i-olat<nl nervous sy-tc in of a Hermit Crab (Kupagurus 



bcmhardut ) . The tr;ni-vcr-e and longitudinal concen- 



Of the components of the subo?so|>liageal-thoracic 



inns* is great <T than in Scyllarus, but posterior to the 



ulicMOphageal .nitre the outlines of four ganglia can be 



traced upon the ventral -iirfac.- of the mass. Three ol 



ihew ore situat.-d in front of the perforation for the, sternal 



artery, and respectively innervate the three anterior pairs 



us. Tlic fourth centre is formed by 



ii ! tin- la>t two thoracic ganglia with the lirM 



inin. d. it iniH-rvati". the two posterior pairs of thoracic 



liuiln* and th- :mt.-rior part of the abdomen. The ma- i- 



<! between the i'.rd ;md lib thoracic ganglia by the 



;ial arliTV. and ha- aUo two minute oj.enings b.-twem 



ill- 2nd and i'.rd and Nt and 2nd: beyond the indication 



b-d by th-i- aprrtun--, :dl cxtrnial traces of connectives 



lo-t. The abdominal chain consist- oi' five |air- of 



-\iT--lv -.ncentrated i united by >eparate 



, . , . .... 



