1905. J ox REGEN'ERATIOX OF THE TAILS OP MICE. 491 



a coiu-esponding way. The dorsal (supra-intestinal) blood-vessel 

 could be distinctly seen through the body-wall, and it branched in 

 the same fashion as the body. Each branch bore its own four 

 rows of setfe. 



Mr. H. B. Fantham, B.Sc, F.Z.S., exhibited and made the 

 following remarks upon microscopic preparations of a new 

 Hfemosporidian parasite belonging to the genus Plroplasma^ from 

 the blood of the white rat : — The parasite is endoglobular and the 

 trophozoites are ovoid (0'5 to 1"5^ in diameter) or pear-shaped 

 (2 to 3 |U long and 1 to l"5ju broad), and usually uninucleate. 

 A single pear-shaped trophozoite often occurs alone in a blood- 

 corpuscle of the host. Some amoeboid forms were seen in the 

 .spleen. Schizogony takes place inside the red blood-corpuscles by 

 simple fission. Double infection of a blood-corpuscle may occur, 

 while free ovoid forms of the parasite have also been seen. 

 For this new species of Piroplasma in the white rat, the name 

 Piroplasma muris is proposed. The parasites are not numerous 

 in the peripheral circulation of the host, but occur in greater 

 numbers in the spleen, liver, and bone-marrow. 



Some of the pathological effects (piroplasmosis) in the white 

 rat, due to this parasite, were anaemia, biliary fever, alopecia, 

 emaciation, ulcers on the ears and tail, enlarged spleen, &c., and 

 proved fatal. 



The genus Firoi)lasma is of great interest, as species of it 

 give rise in various mammals to sei'ious diseases, usvially of the 

 nature of biliary fever. P. bigeminitm is the pathogenic agent 

 of Texas Fever (Redwater) in cattle ; P. canis of malignant 

 jaundice in dogs; P. equi of biliary fever in horses; and P. ovis 

 of similar diseases in sheep. Piroplasmosis may also occur in the 

 human subject, e. g. P. hominis is found in the blood of persons 

 suffering from Spotted or Tick Fever in the Rocky Mountains ; 

 while the Leish man- Donovan bodies found in cases of " Kala- 

 azar" and Delhi boil in India are referi-ed by Lavei-an and 

 Mesnil to this genus, as P. donovani. A Piroplasma has also been 

 stated to have been found in the blood of certain lizards in India, 

 though details have not yet been published. The symptoms in 

 the white rat seem to exhibit a combination of those enumerated 

 in other mammalian hosts. 



Piroplasmosis is usually disseminated by ticks ; but no ticks 

 have yet been found on infected white rats. Perhaps the inter- 

 mediate host in this case is a louse or a flea. No flagellates were 

 found in citrate cultures of the blood of infected white rats, 

 though Capt. Rogers, I. M.S., has obtained flagellates from cultures 

 of P. donovani. 



Mr. Oldfield Thomas, F.R.S., F.Z.S., exhibited the tail-vertebrte 

 of a Dormouse of the genus Eliomys recently received by the 

 British Museum from Central Asia, and stated that it appearie 

 to represent a case of regeneration similar to what occurred in 



