404 
Spirochaetes of Tapes aureus 
(2) All the differences in morphology and in size of the Spiro¬ 
chaetes observed in Tapes aureus are explicable by reference to the 
processes of division and growth. 
(3) The Spirochaete found in the crystalline style of Tapes aureus 
is probably either S. balbianii (which occurs also in the oyster) or a 
variety of the same. 
(4) The creation of several different species of Spirochaetes in 
the same host is not to be commended until a careful study of the 
morphological variation of the Spirochaetes has been made. 
(5) Infection experiments should be carried out before it is assumed 
that each species of Lamellibranch harbours its own particular species 
of Spirochaete. It is probable that S. balbianii is widely disseminated 
among various marine Lamellibranchs. 
(6) Both longitudinal (PI. VI, Figs. 39—44) and transverse 
division (Figs. 49—52) occur in the Spirochaetes of Tapes aureus, 
as in S. balbianii of the oyster, S. anodontae, and the blood-inhabiting 
Spirochaetes S. recurrentis and S. duttoni. It is possible that 
there is a periodicity with regard to the mode of division (trans¬ 
verse and longitudinal) in the Spirochaetes of Lamellibranchs, such 
as Miss Porter and I (1909) have found for S. recui'rentis and 
S. duttoni. 
(7) No evidence of sexual differentiation, conjugation or encyst- 
ment was found while examining the Spirochaetes of Tapes aureus. 
(8) The evidence at hand is insufficient to establish the existence 
of more than one species of Spirochaete in Tapes aureus. 
REFERENCES. 
Borrel, A. (1908). Spirilles, Spirochetes, Trypanosomes. Bull. Soc. Pathologie 
exotique, I. pp. 151—5. 
Borrel, A. et Mlle. Cernovodeanu (1907). Membrane ondulante du Spirochaeta 
balbianii. C. R. Soc. Biol. LXII. p. 1102. 
Breinl, A. (1907). On the morphology and life-history of Spirochaeta duttoni. 
Ann. Trop. Med. (Liverpool ), I. pp. 435—8, 1 pi. 
Certes, A. (1882). Note sur les parasites et les commensaux de l’huiti’e. Bull. 
Soc. Zool. de France, vii. pp. 347—53, 1 pi. 
- (1891). Sur le Trypanosoma balbianii. Bull. Soc. Zool. de France, xvi. pp. 
95 and 130. 
Dutton, J. E. and Todd, J. L. (1907). A Note on the Morphology of Spirochaeta 
duttoni. Lancet , Nov. 30, pp. 1523—5. 
