APPENDIX IV 



303 



did not understand. Claus recognised it as an opening of 

 the shell gland. This, as already shown, we have been 

 able to confirm by following the gland through series of 

 sections. 



Fig. 69. — Sketch of the region about the eyes of an adult specimen of L. productus, 

 showing the relative position and sizes of the dorsal organ, the paired eyes and 

 the pore(/) leading into the water-sacs. At the anterior end of the dorsal organ 

 is seen the fine pore mentioned in the text. 



The Dorsal or Neck-Gla7id. — One more gland in Apus, 

 the neck- or dorsal gland, remains to be mentioned. 

 It shows as an oval spot behind the eyes, and is 



