F. Av. rniT.Lirs— a nkw fl.vgellatic animalcule. 93 



disappears, cilia only being present. The section Flagellata- 

 customata is divided into nine families ; we have to deal with the 

 fifth, called Chrysomonadina^ (xi'>"^'"'j S^^^^^ ! fioi'o^, sinf^le). Of 

 this family I will give you the diagnosis contained in Mr. Savillo 

 Kent's Manual. 



" Animalcules hi- flagellate, rarely mono-flagellate, social or 

 solitary, free swimming or adherent, naked, loricate or immersed 

 within a common matrix or zoocytium ; endoplasm always contain- 

 ing two lateral differentiated pigment-bands, occasionally green but 

 more usually olive-brown or yellow ; one or more supplementary 

 eye-like pigment-spots frequently present." 



The animalcules included in this family group were for a long 

 time held to be approximate to Vohox, Protococciis, and other 

 unmistakable protophytes, and it is only recently that their 

 undoubted animal organization has been substantiated. 



The family Chrysomonadiune is divided into fifteen genera : — 

 Chhromonas, C/iri/.soi/tonas, Microglena, Crijptomonas, Nephromlmis, 

 Sfylofhrysalis, Uvella, Chloranginuni, Ht/menoinojian, Ghrysopijxsis, 

 Epipi/xsis, Dinohrijon, Si/nura, Suncri/pta, and Urofilena. 



The single species, Si/nura Uvella, which constitutes the genus 

 Si/nura, most nearly resembles our new animalcule. In the genus 

 Si/nura the animalcules are united in spheroidal clusters which 

 swim freely through the water. Each zooid inhabits a closely- 

 fitting lorica of a pear-shaped contour, which is beset with short 

 spinous processes. There are two flagella of equal length. The 

 endoplasm contains two lateral pigment-bands in which ai'e de- 

 veloped two minute, coloured, pigment eye-like spots. A large 

 vascular space exists at the anterior extremity, which is supposed 

 to fulfil a pharyngeal office. There are three contractile vesicles 

 situated at the anterior extremity. The spherical clusters consist 

 of as many as eighty zooids. 



The animalcules which are now for the first time recorded, exist 

 in colonies of about thirty zooids, grouped together in a chain-like 

 manner, and possibly united by a contractile, hyaline ligament 

 of extreme delicacy. The constituent zooids each inhabit a closely- 

 fitting lorica of a somewhat triangular aspect, pointed anteriorly, 

 and twice the width posteriorly at the point of attachment. The 

 lorica is covered with very minute spinous processes of even 

 length. At the anterior extremity there is a slight indentation, in 

 the centre of which is the oral aperture, which is continued into 

 a short, distinct, triangular, pharyngeal cleft or cavity. Seen 

 from a side view, the lorica has an oval aspect. The flagella are two 

 in number and of equal length, issuing from the pharyngeal cleft. 

 The endoplasm contains the two characteristic lateral pigment- 

 bands ; there are no eye-spots ; one contractile vesicle is developed 

 posteriorly. 



The most remarkable characteristic in connection with these 

 colonies is the peculiar movements, which are of a twofold nature. 

 The first consists of an elongation and corresponding retraction of 

 the whole chain of zooids to about five times the retracted length. 



