48 



VII. Maxilliped. 

 * Chilarion. 



VIII. Lid-plate. 



IX. First gill-plate. 



X. Second gill-plate. 



XI. Third gill-plate. 



XII. Fourth gill-plate. 



XIII. Fifth gill-plate. 



b. Dorsal wall of cephaletron. 



c. Ventral wall of cephaletron. 



d. Digging-border of cephaletron. 



e. Holding-border of cephaletron. 

 g. Entering process of thoracetron. 

 h. Entosternon. 



i. Intestine. 



in 1. Levatores thoracetri. 



m 7. Levatores telsi. 



m 8. Obliqui telsi. 



m 9. Depressores telsi. 



n a. Ocellar nerve. 



n A. Ocular nerve. 



« II. Antennular nerve. 



n III. Antennal nerve. 



n IV. Mandibular nerve. 



n V. Premaxillary nerve. 



n VI. Maxillary nerve. 

 » VII. Maxillipedal nerve. 

 n VIII. Opercular nerve. 

 n *. Chilarian nerve, 

 w ix-xiir. Nerves to branchigerous limbs- 

 re XIV. Nerve of anal segment. 

 0. Ostia venosa. 

 pi. Pleonic plexus. 

 r. Muscular wall of heart. 

 s. Neural artery. 

 t. Pleonic artery. 



a. Brain, or superoesophageal nervous centre. 

 )3. Neural ring. 

 7. Neural cords. 

 S. First ganglion. 

 e. Second ganglion. 

 5. Third ganglion. 

 77. Fourth ganglion. 



Fifth or terminal ganglion. 



Ganglionic loop. 



Pleonal nerve, or continuation of neural cord. 



Principal nerve of 



Pleonal plexus. 

 a 1-4. Dorsal nerves of four anterior coalesced 

 pleonal segments. 



e. 



X- 

 X. 



fi. 



pi. 



Fig. 2. Outline of figure 3, Plate II, giving a vertical longitudinal section of fore part of cephaletron and 

 alimentary canal, with the cephaletral limbs or appendages of the left side. (The Preparation 

 is No. 477 a, in the Physiological Series of the Museum of the Royal College of Surgeons : 

 'Descriptive and Illustrated Catalogue,' 2nd ed. 8vo, 1852, p. 132.) 



m. Posterior hepatic duct. 



A, II to VII, and *, as in figure 1. 



b. Dorsal wall of cephaletron. 



c. Ventral wall of cephaletron. 



d. Digging-border. 

 /. Chitine. 



g. Pigment-layer. 



ce. (Esophagus. 



h. Entosternon. 



t. Intestine. 



/. Anterior hepatic duct. 



p.p. Carding-plates, or palpi, of haunch-joints 



of III-VII. 



*. Chilarion, a seemingly serial repetition of 



haunch-joints. 

 q. Median lobe of ovary, 

 r. Proventricular or cardiac part of stomach. 

 s. Gizzard. 

 mt. Pyloric prominence. 



Fig. 3. Outline of the maxilla (6th cephaletral limb). 



1. Coxa. 4. Cnemion. 



p. Its " palp," or carding-plate. 5. Propes. 



is. Basis. 6. Dactylus. 



3. Merion. 



