INTERNAL ANATO^rV OF SQUILLA. 
428 
II. Notes on some other Features oe the Internal Anatomy 
OF Squilla. 
'J^he Communications between the Pyloric Diges- 
tive Gland (''Liver”) and the Gut. 
Johannes Muller (29) in 1830 made the statement that the 
so-called "liver” possessed numerous pairs of segmentally 
arranged openings into the alimentary tract, and later authors 
(e.g. Duvernoy, 1836 [26], Milne Edwards, 1859 [27], Ger- 
staecker, in Bronn’s ' Thierreich,’ 1889 [31] and others) have 
either accepted this statement on MhlleFs authority or have 
supposed that their reinvestigations have confirmed Muller. 
However, in 1901 Orlandi (30) to a large extent correctetl 
this erroneous idea, and stated that the two halves of the 
" liver ” solely opened into the gut by a single median opening 
into the dorsal side of the pyloric part of the stomach, and this 
statement has appeared in most recent English text-books, 
e.g. in CalmaiFs " Crustacea” in LankesteFs ' A Treatise on 
Zoology ^ and Sedgwick^s ' Student’s Text-book of Zoology.’ 
It must be pointed out, however, that Fritz Muller (28) in 
1863 clearly described and figured a single pair of "liver” 
ducts opening into the sides of the stomach in an Erichthus 
larva, and this fact would by itself lead us to suppose that the 
adult condition is similar to that of the larva. 
A further correction concerning this much misinterpreted 
and, indeed, trivial point of fact has now to be made in the 
present paper. Orlandi was correct in stating that each half of 
the "liver” only possesses a single duct opening into the pyloric 
region, but quite wrong in stating that the two ducts unite 
together and open by a single mid-dorsal aperture. Examina- 
tion of complete series of transverse and longitudinal sections 
through the adult Squilla desmarestii, Risso, shows that 
each duct opens independently into the side of the pylorus 
by a large triangle-shaped aperture (the apex of the isoceles 
triangle being anterior and the vertical base posterior), and 
so conforms to the arrangement found in most Crustacea. In 
