230 
PACIFIC SCIENCE, Vol. XV, April 1961 
Again, there was a definite amylase reaction from 
each organ. 
The positive results seem unusual in view of 
the fact that most vertebrates ( except for mam- 
mals which secrete ptyalin in their saliva ) break 
down starch initially with pancreatic amylase 
and complete the process with intestinal maltase. 
These results on the manini seem less dubious, 
however, in the light of the finding by Kenyon 
of amylase throughout the whole gut of the carp 
( although it was considered to lack a true stom- 
ach) and by the detection of stomach and duo- 
denal amylase in Zoarces by MacKay. Also Bab- 
kin and Bowie found amylase in the intestine 
of the killifish. They were certain it was not 
adsorbed pancreatic amylase, for they were un- 
able to observe any proteolytic action in the same 
extract. 
Pancreatic amylase of the manini is nearly 20 
times more powerful per unit of tissue than the 
amylase from other organs, while that from the 
stomach was weakest (attempts were made to 
obtain extracts from equal amounts of glandular 
tissue of the organs under comparison). 
The pH optimum of the amylase, as deter- 
mined by color change with Lugol’s solution and 
the micro method of Linderstr0m~Lang (Linder - 
str0m-Lang and Hoi ter, 1933), is 6.7. 
The Schoorl method was utilized to test for 
the presence of maltase in the stomach, pyloric 
caeca, pancreas, duodenum, and intestine of the 
manini. One per cent maltose solution served 
as the substrate. Trials for all organs were run 
at pH 7.0 and 7.2 and incubated at 30° and 
35° C for periods up to 12 hr., but results were 
consistently negative. 
The method of Michaelis and Rona (see van 
Weel, 1937: 245) was used in lipase experi- 
ments. Tri-n-butyrin solution was used for the 
substrate. Digestion occurred rapidly in all the 
organs tested. It was evident that the pancreas 
produced the most lipase and the stomach the 
least, although the difference was not as marked 
as with amylase. The pyloric caeca showed the 
greatest lipase activity of the remaining organs. 
Difference between the duodenum and the rest 
of the intestine was not discernible. The pH 
optimum determined for pyloric caeca lipase of 
the manini is 7.2. 
Detection of protein digestion was based on 
the formaldehyde titration of Sorensen (Jordan, 
1927). The substrate was a 3 per cent colloidal 
solution of gelatin. 
In initial experiments protease was found in 
the pancreas, pyloric caeca, duodenum, and in- 
testine, but not in the stomach. In none of the 
organs was the proteolytic activity strong. The 
pH optimum of pancreatic protease is 8.4. 
Because of the acidic reaction in the stomach 
of the manini and the knowledge that protease 
in this organ can vary widely from individual 
to individual depending on the state of hunger 
of the animal (Schlottke, 1939), further effort 
was expended to localize this enzyme in the 
stomach. Extract of high concentration (pre- 
pared from trituration in 5 ml. of 50 per cent 
glycerol of three adult manini stomachs, two of 
which contained considerable algae) finally gave 
positive results. One ml. of this concentrated 
extract (thus containing the extractable enzyme 
from three-fifths of a stomach ) at pH 6.0 yielded 
acid equivalent to 0.2 ml. of 0.015 normal so- 
dium hydroxide after 4 hr. of incubation. 
A piece of the very thin covering (one cell 
layer thick) from one of the internal rings of 
an onion was peeled off and placed in a glass 
stender and covered with the fluid from the in- 
testine of an adult manini. The onion skin was 
examined after 24 and 48 hr. periods, but no 
digestion of the cellulose cell walls occurred. 
The experiment was repeated with fluid from 
the intestine of another adult specimen, again 
with negative results. Thus there appears to be 
no cellulase-secreting micro-organisms in the 
intestine of the manini. 
It is concluded that the results of the enzyme 
study of the manini are consistent with the gen- 
eralization previously made concerning the di- 
gestive enzymes of herbivorous animals except 
for the absence of cellulase. 
REPRODUCTION 
Sex Ratio 
No sexual dimorphism in external morphol- 
ogy was noted; therefore gonad examination was 
necessary for sex determination. The gonads lie 
in the ventroposterior part of the body cavity. 
No difficulty was experienced in distinguishing 
an ovary from a testis macroscopically except 
with immature fish. The ovaries are pinkish 
