300 APPENDIX III 



from the dorsal shield after bathing the shell glands. As 

 far, however, as anatomical researches enable us to judge, 

 we cannot confirm Zaddach's statement that it returns to 

 the heart through special venae branchiales. We think that 

 when this point comes to be further investigated it will 

 probably be found that the blood, which enters the shield 

 laterally, circulates round through it, and returns to re-enter 

 the body anteriorly and dorsally ; not, however, to enter the 

 cardial sinus, but rather to descend on each side of the 

 cephalic aorta, bathing the mandibular muscles on its 

 way to join the main stream from the head into the 

 intestinal sinus. 



