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doubtless gain access to the digestive gland (“liver”) by passing along 
the numerous small ducts that finally unite into one leading from the 
“liver” to the stomach of the limpet. 
Systematic Position. 
The flagellate parasitic in Patella vulgata is a member of the genus 
Herpetomonas as originally defined. It is considered to be a new 
species, H. patellae. It shows the following characteristics among others. 
H. patellae is much smaller than any other Herpetomonas yet described, 
its body being only 5 p, to 7 p, long. The relatively large size of the non- 
flagellate stages of the organism is not common among other herpe- 
tomonads. The movements of H. patellae are more jerky than those 
of most other herpetomonads and the “boomerang” movement is 
unlike that described for any other species, so far as I am aware. Its 
occurrence in the digestive gland of a mollusc is believed to be unique 
at present. 
Remarks on the pathogenic significance of certain Flagellates found 
in Invertebrates. 
During the last few months, thanks to the interesting investigations 
of Laveran and Franchini, the importance of herpetomonads and 
Crithidia has greatly increased from the pathogenic point of view. 
Laveran and Franchini’s first series of experiments (Sept. 1913) showed 
that Herpetomonas ctenocephali (Fantham), parasitic in the gut of the 
dog flea, Ctenocephalus canis, could be inoculated intra-peritoneally 
and otherwise into white mice with fatal results. Leishmaniform 
parasites were found in the blood and internal organs of the mice, 
especially in the liver. A very few flagellate parasites only were seen 
in the inoculated vertebrate. Eats and a dog were also inoculated. 
The dog died, leishmaniform parasites being found m the internal 
organs. The infection could be maintained by successive inoculations 
into clean vertebrates. 
Similar experiments were made with Crithidia fascieulata (Leger), 
parasitic in the gut of Anopheles macnlipennis. The experiments began 
with the successful inoculation of the contents of the digestive tract 
of parasitised Anopheles into rats and mice. 
Further experiments were undertaken with Herpetomonas pattoni 
(Swingle), parasitic in the gut of the rat flea, Ceratophyllus fasciatus. 
White rats and white mice became infected when kept in contact with 
numerous parasitised rat fleas. It was then shown that the mode of 
