SPECIAL ANATOMY. 63 



long muscular cylinder, a little curved downward at the posterior part. 

 There is no cul-de-sac for the lingual lamina protruding behind ; and 

 the retractor muscle is divided into three fasciculi, one central and pass- 

 ing into the buccal body posteriorly, the others lateral and inserted as 

 usual. Externally, it has a very thin investment of longitudinal mus- 

 cular fibres, continuous with those of the retractor muscle and the ori- 

 gin of the especial muscles of the tongue. This layer is very delicate 

 and transparent ; and at the anterior third of the buccal body, laterally 

 and inferiorly, it presents several fasciculi, which pass to the tegumen- 

 tary lips. Beneath the exterior covering, and readily seen through it, 

 is a thick and strongly fasciculated, transverse layer of muscular fibres. 

 When the buccal body is laid open the oral orifice is found to be con- 

 tinuous with a triangular canal with smooth sides, running one third its 

 length. At the posterior superior termination of the canal is the open- 

 ing of the oesophagus and orifices of the salivary ducts. There is no 

 dental plate, or jaw. The posterior two-thirds of the buccal body is 

 occupied by a long oval organ, composed of numerous, strong fasciculi of 

 muscular fibres, arising laterally and inferiorly at the posterior part of 

 the buccal body ; the former passing inwards and forwards, the latter 

 forwards to the anterior extremity of the organ, which is free, and pro- 

 jects into the triangular, oval canal. The lateral fasciculi leave between 

 them superiorly an interstice, at the bottom of which is found the lin- 

 gual membrane, in the form of a tube, closed posteriorly, and open and 

 reflected downwards and backwards upon the anterior, free tip of the 

 organ. Into the posterior extremity of the lamina the middle fascicu- 

 lus of the retractor muscle of the buccal body is inserted ; and, just 

 anterior to this insertion, a small, attrahent fasciculus, arising from the 

 roof of the buccal body, posterior to the orifice of the oesophagus, which 

 gets to the lamina by means of the interstice of the muscular organ 

 superiorly. The teeth of the lingual membrane are arranged diagonally, 

 from the middle line, in parallel rows, passing from within outwards, as 

 shown in the descriptive portion of this work. 



The oesophagus issues from a fissure at the upper posterior line of 

 the anterior third of the buccal body. It is long and cylindrical, and 

 rather wider at its termination than at its origin. The stomach is 

 irregularly cylindroid, and has a cul-de-sac at its commencement, pro- 

 jecting anterior to the entrance of the oesophagus. The small intestine 

 is capacious. 



The salivary glands are conjoined, so as to form a circular collar 



