176 MR W. E. HOYLE ON 



2. The (Esophagus commences at the bottom of the groove posteriorly, and 

 after a variously curved course, opens into the ventral surface of the stomach 

 some distance behind its anterior extremity (PI. XXVII. fig. 8, oe). Its course 

 is at first obliquely upwards and backwards, and its transverse section is cres- 

 centic, the horns being directed ventrally (fig. 6, r) ; the dimensions of this 

 crescent are 016 mm. across the horns, while the lumen of the passage is only 

 0012 mm. in width. This portion of the oesophagus is lined with chitin pro- 

 longed from the external covering of the body ; and its wall is composed of a 

 mass of cells in which distinct muscular elements could not be made out. 



The oesophagus then turns directly backwards to pass beneath the anterior 

 nerve commissure (fig. 8, a.n.c), and at this point its structure undergoes a 

 change ; the cuticular lining after becoming gradually thinner, entirely dis- 

 appears, and outside the cellular wall there lies a covering of muscular fibres 

 arranged as a sphincter ; while, in addition to all this, the section of the tube 

 becomes irregularly elliptical instead of crescentic, the transverse and dorso- 

 ventral diameters being 0*1 mm. and 0'012 mm. respectively. 



When the oesophagus has passed through the nerve collar, its direction 

 tends more upwards, and very slightly forwards, and its lumen assumes an 

 irregularly stellate form, owing, probably, to the contraction of the sphincter 

 muscles, and consequent puckering of the cellular lining (fig. 6, /). It now 

 turns backwards, and at the same time comes to lie in a mass of cells situated 

 immediately below the intestine. The elements composing this mass are for 

 the most part of ovoid form, the greatest diameter averaging 0016 mm. ; they 

 have a finely granular content, and a large deeply-stained spheroidal nucleus, 

 with a nucleolus. Their function must remain to a large extent the subject of 

 conjecture ; their histological characters and situation would suggest that they 

 form a gland, but none of the sections examined have revealed any trace of 

 duct or of excretory openings in the oesophageal wall. 



After a short course through this gland-like organ, it turns directly upwards, 

 and opens upon a small elevation in the floor of the intestine, at a point about 

 1 mm. behind its anterior extremity (PI. XXVII. fig. 8). 



3. The Stomach (Chylusmagen of Leuckart) needs only a few words of 

 description. As stated above, it presents anteriorly a rounded coecal extremity 

 about 0*5 mm, in length, behind which is the opening of the oesophagus (PI. 

 XXVII. fig. 8). Its form is, speaking roughly, cylindrical, slightly tapering, 

 however, as it passes backwards, and it lies evenly in the middle of the body 

 cavity ; its greatest diameter being about 075 mm. A little less than 1 mm. 

 from the posterior extremity of the body the stomach terminates by opening 

 into the rectum. 



Of all the organs of the body the digestive tract was, unfortunately, the 

 worst preserved, so that I am unable to give information of any great value as 



