Phibdinaea.] THE INFUSORIA. 405 



wheels withdrawn, which is the case when crawling; the 

 respiratory tube is then seen, terminated by a single deli- 

 cate hair-like point ; Jig 482 shews one contracted, but the 

 head partially withdrawn ; fig. 484 represents the upper 

 part, when the wheels are extended and in action ; fig. 483 

 is the oesophagus and jaws, separated and extended under 

 the pressure. Length l-36th to 1-1 8th. 



Genus CLXXXIII. Monolabis. These Philodhiean 

 Rotatoria have two frontal red eyes, and a foot with two 

 toes, but no horn-like processes. They are provided with 

 muscles for moving the double rotatory apparatus, two for 

 moving the foot, and four belong to the oesophagal head 

 and jaws, which latter are furnished with double teeth, or 

 teeth in rows. A very short oesophagal tube, and a simple 

 conical alimentary canal, are seen in both species, one of 

 them has two spherical biliary glands ; an ovarium is seen 

 in both, but in neither has fully-developed ova or male 

 organs been observed. In one species a respiratory tube 

 is present. 



697. Monolabis conica. The stout Monolabis. — Body 

 stout, provided wdth a respiratory tube, or spur, and three 

 teeth in each jaw. Between the rotatory organs the brow 

 can project and resemble a proboscis. Figures 485, 486, 

 represent different views from the under side. Length 

 1 -120th. 



698. Monolabis gracilis. The slender Monalabis has a 

 more slender body than the last, and two teeth in each 

 jaw, but no respiratory tube or spur. Length about 

 1 -200th. 



Genus CLXXXIV. Philodina. The necked Rota- 

 toria have two cervical eyes, and horn-like processes to the 



