CHITIN IN THE CARTILAGES OF LIMULUS AND SEPIA. 173 
On the Occurrence of Chitin as a Constituent 
of the Cartilages of Limulus and Sepia. 
By 
W, D. Halliburton, K.D., B.Sc., 
Sharpey Physiological Scholar, University College, London. 
(From the Physiological Laboratory, University College, London.) 
The question of the chemical composition of the cartilage 
that occurs in various invertebrate animals does not seem to 
have been the object of previous research . 1 In an article 
by Professor Lankester on “ The Skeleto-trophic tissues of 
Limulus,” which appeared recently in this Journal , 2 he states 
that Professor Schafer having, at his request, chemically 
examined the ento-sternite of that animal, had found that 
chitin was probably present in that organ. Professor Lankester 
subsequently placed a larger supply of this tissue in my hands 
for the purpose of determining the presence of chitin; in 
addition I have, at Professor Lankester’s suggestion, submitted 
to a similar examination the cartilage found in the head of the 
cuttle-fish (Sepia). 
These cartilages are in appearance similar to that found in 
vertebrate animals ; but chemically they are different, as they 
contain chitin in addition to a chondrin-like body. 
We may consider the subject under the following heads: 
a. Composition of the Cartilage of Sepia. 
b. Composition of the Entosternite of Limulus. 
c. Existence of Chitin in the Liver of Limulus. 
1 In his paper recently published on the subject of cartilage, Krukenberg 
makes no reference to the cartilage of the two animals I have examined. 
Krukenberg, “ Die chemischer Bestandtheile des ^norpels,’’ ‘ Zeitschrift fur 
Biologie,’ xx Band, 3 Heft, Miinchen und Leipsig, 1884. 
2 ‘ Quarterly Journal of Microsc. Science,’ Jan., 1884. 
