232 Proceedings of the Royal Physical Society. 



potash, so that many of the separated spicules appeared 

 bifid. That this was artificial was evident from an examina- 

 tion of a thin longitudinal slice, which showed no split 

 spicules. There was no trace of minute flesh-spicules or 

 microscleres. 



The nature of the skeleton — spongin-fibres, with imbedded 

 styles forming a firm axis — points to the family Axinellidse. 

 In this family the genus Axinella, 0. Schmidt, is character- 

 ised by having a firm-branched axis, composed of a spongin- 

 network, with included siliceous styles. To this genus, 

 therefore, we refer the " Scotia " specimen, but although the 

 species is probably new, it is impossible to determine this 

 with certainty, as only the axial skeleton is preserved. 



XIX. Notes on certain Blood- Inhabiting Protozoa. By Murtel 

 EoBEiiTSON, Carnegie Eesearch Scholar in the University 

 of Glasgow. [Plates VIII. and IX ] 



(Read 26th March 1906.) 



During the last six months I have had the opportunity of 

 examining a number of different haemosporidial forms. These 

 notes embody some of the points of interest that have 

 appeared during the course of the work. 



I am glad to have this opportunity of acknowledging how 

 much I owe to the guidance and encouragement of Professor 

 Graham Kerr, under whose supervision the work was 

 conducted. 



The forms dealt with in this communication are — (1) 

 Trypanosoma hrucei ; (2) Trypanosoma pythonis, n.sp., an 

 endocorpuscular form from the blood of an African python ; 

 (3) a Trypanosome found in the blood of Pleuronectes p)latessa 

 and Pleuronectes flesus ; (4) a Hsemogregarine, also found in 

 the blood of the two last-mentioned hosts; (5) T. raice 

 (Laveran and Mesnil) ; and (6) a Hsemogregarine found in 

 the erythrocytes of Raia microcellata. 



1. Trypanosoma brucei. 



Prowazek, in his work upon Trypanosoma hrucei, gives an 

 account of the more important processes in the lile-history 



