768 



ZOOLOGY 



SECT. 



oesophagus, supported and protected by the cranial cartilage. The 

 cerebral ganglia (cer. g.) are fused together into a rounded mass, 

 lodged in a hollow of the cranial cartilage, and covered over 

 anteriorly by a strong fibrous membrane. Laterally are given off 



Fig. t>o3.— Sepia cultrata, lateral dissection of male. The left-hand half of the head has 

 been removed by an approximately median longitudinal section, the buccal mass, however, 

 being left intact ; the funnel and the anterior and posterior walls of the mantle-cavity are 

 likewise bisected longitudinally. The left ctenidium with the left nephridial sac and 

 left branchial heart have been removed from their natural position and displaced backwards 

 so as to expose the other organs. The digestive gland with its ducts and the pancreatic 

 appendages have been removed, but the position of the former is indicated by a dotted line. 

 app. appendage of left branchial heart ; aort. aorta ; aort'. aboral aorta ; hue. buccal mass ; Or. 

 cart, section of cartilage supporting the arms ; cer. g. cerebral ganglia ; ffiz. gizzard ; ink. s. 

 ink-sac ; in/, funnel ; jaio, jaw ; I. aur. left auricle ; I. br. ht. left branchial heart ; I. cten. 

 left ctenidium ; lie. position of digestive gland ; /. neph. left nephridial sac ; n. cart, nuchal 

 cartilage ; est. oesophagus ; ot. cavity of statocyst laid open ; ped. g. section of pedal gang- 

 lion ; perist. peristomial membrane ; post. v. abdominal vein ; r. aur. right auricle ; r. cten. 

 right ctenidium ; rect. rectum ; sal. salivary gland ; sh. shell ; st. stomach ; tc. testis ; va. 

 valve of funnel ; *;. cav. vena cava ; vent, ventricle. 



a pair of short thick processes — the optic nerves or optic stalks 

 (opt. st.) — which expand almost immediately into large masses — 

 the optic ganglia (opt. g.) — in immediate contact with the eyes. 

 At the sides and posteriorly a pair of very thick commissural 

 bands of nerve-matter pass round the oesophagus to unite with the 



