140 Prof. H. James-Clark on the Spongite ciliatse 



and often-repeated retrocession. Upon putting on a power of 

 eight hundred diameters, the Avhole organization was brought 

 out with sufficient clearness to satisfy one upon every point. 

 For the purposes of illustration, however, it was thought best 

 to increase the magnifying-power to a still greater extent ; and 

 we have, therefore, drawn one figure (fig. 34) to represent this 

 infusorian as it appears Avhen seen under an amplification of 

 about fifteen hundred diameters. 



This animal has never been found in a free state, or in any 

 other than that which is represented in these two figures 

 (figs. 34, 35). It has an elongate oval body, which is enclosed 

 in a deep vasiform, pedicellated calyx (c), to whose bottom it 

 is attached by a slender, colourless, contractile ligament (r). 

 It usually rests about halfway between the top and bottom of 

 the calyx, but is frequently jerked to the bottom (fig. 35) of 

 the vase (c) by means of the ligament just mentioned. The 

 anterior end is tnnicate, and prolonged into two prehensile 

 organs, one of which is aJfageUum (Jl), and the other a lij) {Jp) 

 similar in position and function to that of the Monas described 

 in the previous section. The generally prevailing fuscous tint 

 is interrupted by a transparent colourless streak (z-^), which 

 extends from the laterally posited base of the flagellum {fl) to 

 the posterior end of the body, where it seems to be prolonged 

 into the contractile ligament (r). It is not a band, however, 

 but a sharply defined furrow, of considerable depth. At the 

 anterior end it is sunk so deeply that it borders closely upon 

 the base of the flagellum, and from that point it gradually 

 shallows until it nearly disappears at the point of junction of 

 the body with the contractile ligament. 



We are thus reminded of those heteronematous Flagellata, 

 like Anisonema (figs. 65—69), whose bodies are so conspi- 

 cuously sulcated in a longitudinal direction ; and the apparent 

 continuity of the retractor ligament (fig. 34, r) with this 

 furrow (?•') heightens the impression, by its resemblance to the 

 highly muscular trailing lash (figs. 65-69, j^°) of that genus. 

 One could hardly be accused of unduly straining a point in 

 homology if he were to regard the furrow (fig. 34, r^) in 

 question as merely a greatly prolonged ostial notch, and the 

 retractor (r) as a trailing lash, which originated at the greatest 

 possible distance from the other, its proboscidal companion {fl). 



The Uj) {^j)) is a more prominent organ than that of Monas. 

 It has a conical shape, and is about twice as long as its greatest 

 breadth. It is so hyaline as to readily escape notice until it is 

 fully recognized. It is situated at the edge of the truncate 

 front opposite to that from which the flagellum arises, and 

 therefore leaves a considerable space between the latter and 



