hepatic caecum
Hepatic caecum or hepatic cecum is a name used in describing various physiological structures in some crustaceans, insects and lancelets. "Hepatic" refers to the liver, and the hepatic caecum may perform some functions that are analogous to the functions of the liver in vertebrates (except for lancelets, whose "proto-liver" is homologous).
''Amphioxus''
A digestive organ called the hepatic caecum is found in the cephalochordate amphioxus, or lancelet.{{cite web |url=http://www.ucmp.berkeley.edu/chordata/cephalo.html |title=Introduction to the Cephalochordata |publisher=University of California Museum of Paleontology |last=Waggoner |first=Ben |date=February 7, 1996 |accessdate=January 20, 2014}}{{cite web |url=http://lanwebs.lander.edu/faculty/rsfox/invertebrates/branchiostoma.html |title=Amphioxus |last=Fox |first=Richard |publisher=Lander University |date=July 5, 2006 |accessdate=January 20, 2014}} The hepatic caecum of the amphioxus is a presumed homologue of the vertebrate liver,{{cite journal |url=http://www.actabp.pl/pdf/1_2008/27s.pdf |title=Tissue- and stage-specific expression of a fatty acid binding protein-like gene from amphioxus Branchiostoma belcheri |journal=Acta Biochimica Polonica |volume=55 |number=1 |pages=27–34 |date=2008 |last1=Wang |first1=Yongjun |last2=Zhang |first2=Yuequn |last3=Zhang |first3=Shicui |last4=Tian |first4=Jianxiao |last5=Jiang |first5=Shengjuan |doi=10.18388/abp.2008_3197 |accessdate=January 20, 2014}} although it is not undisputed.{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 18–21|isbn= 0-03-910284-X}} This homology was first hypothesized by Müller in 1844.
Crustaceans
Insects
In some insects, such as the grasshopper, several pairs of hepatic caeca secrete enzymes into the stomach where they assist in the digestive process.{{cite book|author1=Singh, Lakhmir |author2= Kaur, Manjit |title=Biology For Tenth Class: Part3 |url=https://books.google.com/books?id=1QcVlkhsYgsC&pg=PA25 |publisher=S. Chand |isbn=978-81-219-2293-7 |pages=25–26}}