The Microscope, 35 



two globular, refractive vacuoles not connected with the ends of the 

 vascular bulbs, and one of them eventually disappeared. They 

 may have been contractile vesicles. Plate I, fig. 7, shows the 

 outline of the head of this species. 



5. Chcetonotus gracilis, Gosse. 



The body is, here, long and narrow; the head is somewhat 

 three-angled, with five distinct, rounded lobes, and is abruptly 

 joined to the narrow neck. The oesophagus is very long, extending 

 to the middle of the body, and, just before it enters the intestine, 

 the thick, muscular walls suddenly narrow till they seem commen- 

 surate with the tube itself. The hairs on the anterior body-half are 

 set in quincuncial order, and the fine bristles on the back and sides 

 are recurved. This, which I have not seen, would be readily recog- 

 nized by the very unusual structure of the oesophagus, 



6. Chcetonotus brevis, Ehr. 



Ehrenberg's description of this species, which I have not met 

 with, is: — Body short, oval-oblong, slightly constricted near the 

 enlarged front, having few dorsal hairs, the posterior ones being the 

 longest. The eggs are small. Length -^^ inch. 



7. Chcetonotus loricatus, sp. nov. — Plate II, figs. 16 — 21; 

 Plate I, fig. 5. 



The entii'e body, with the exception of the caudal prolongations 

 and the narrow ventral space between the two longitudinal bands of 

 cilia, is covered by imbricated, apparently sub-semicircular scales, 

 their rounded and unattached margins being directed towai'd the 

 animal's head, or in a direction opposite to that of the scales of a 

 fish, thus giving the body a strange but beautiful appearance. The 

 free margins of these transparent scales seem to be thickened, 

 but this may be illusory, and is omitted from the figure (Plate II, 

 fig. 16). These appendages extend around the lateral borders to 

 the outer edges of the ciliary bands, where they cease. The ventral 

 interspace is naked. In addition to the ventral cilia, there is, on 

 each side of the oral annulus, a tuft of cilia, continuous with the 

 anterior clusters of the tactile hairs (Plate I, fig. 5). They, as 

 well as the tactile bristles, are adcurved, and their function seems 

 to be to create a food-bearing current, while that of the ventral 

 bands is chiefly locomotive. The animal is -^^gj inch long. Its 

 movements are rapid and erratic when first placed on the slide, but 

 it soon settles down to a comparatively quiet search for food. 



