iSgS. 



NOTES AND COMMENTS. 



289 



Table of Coincidences between Limiilus and its Allies, and Ammoccetes 

 and Vertebrates {after Gaskell). 



LiMULUS AND ITS ALLIES. 



Central Nervous System. 



Supra-oesophageal ganglia 



Optic part 



Olfactory part 

 CEsophageal commissures 

 Infra-cesophageal ganglia. . 



Prosomatic ganglia . . 



Mesosomatic ganglia . . 

 Ventral chain. 



Metasomatic ganglia. . 

 Alimentary Canal. 



Cephalic stomach . . 

 Straight intestine . . 



Terminal part . . 

 Oesophagus . . 



Mouth tube 



Liver 



Appendages and Appendage Nerves. 



Prosomatic or locomotor appen- 

 dages 

 Foremost appendages 

 Last appendages 



Metastoma 

 Nerves of prosomatic appendages 

 Mesosomatic or branchial appen- 

 dages 

 Opercular appendages 

 Genital part 

 Branch, part 

 Basal part 

 Branchial appendages 



Special Sense Organs and Nerves. 



Lateral eyes and optic nerves . . 

 Median eyes and nerves . . 

 Camerostoma and olfactory nerves 

 Flabellum and nerve 

 Epimeral nerves to surface of pro- 

 soma and mesosoma . . 



Internal and External Skeleton. 

 Internal skeleton. 



Branchial cartilages . . 

 Entapophysial cartilaginous 



ligaments 

 Fibro-massive tissue (fore- 

 runner of cartilage or 

 " Vorknorpel ") . . 

 External skeleton. 

 Chitinous layer 



Excretory Organs and Ccelomic Cavities. 



Coxal gland . . 



1st head cavity, prseoral . . 



2nd head cavity. Cavity of pro- 

 somatic segments 



Cavities to each mesosomatic seg- 

 ment 



Ammoccetes and Vertebrates. 



Cerebral hemispheres. 



Optic thalami, ganglia habenulae, &c. 



Olfactory lobes. 



Crura cerebri. 



Epichordal brain. 



Hind brain, cerebellum, post-corp.quadrig. 



Medulla oblongata. 



Spinal cord. 



Ventricular cavities of brain. 



Central canal of spinal cord. 



Neurenteric canal. 



Infundibular tube and saccus vasculosus. 



Hypophysial tube, later nasal canal. 



Part of subarachnoideal glandular tissue. 



\ Appendages of oral chamber or stoma- 

 ( todaeum. 



Upper lip and tentacles. 



Velar appendage and median ventral 

 tentacle. 



Lower lip. 



Various branches of Vth nerve. 



Appendages of branchial chamber. 

 Appendage innervated by Vllth nerve. 

 Thyroid gland & pseudo-branchial groove. 

 Hyobranchial. 

 Septum of stomatodaeum. 

 Branchial appendages innervated by IXth 

 and Xth nerves. 



Lateral eyes and optic nerves. 

 Pineal eyes and nerves. 

 Olfactory organ and 1st nerve. 

 Auditory organ and VIII th nerve. 



Sensory part of Vth nerve. 



Branchial cartilages. 



Subchordal cartilaginous ligaments. 



Muco-cartilage or " Vorknorpel." 



Cuticular layer on surface of body and 

 subepithelial laminated layer. 



Pituitary gland . 



1st head cavity, praeoral. 



2nd head cavity, mandibular. 



Cavities of hyoid and branchial segments. 



Heart and Vascular System. 

 Dorsal heart 



Longitudinal venous sinuses 

 Lacunar blood spaces of 

 pendages 



Columnof fatty tissuedorsal to spinal cord. 

 Heart and ventral aorta, 

 ap- "I Lacunar blood spaces in velar and 

 J branchial appendages. 



