28 Proceedings of the Royal Society of Victoria. 



the foot (Fig. 4, s.c.g.) not found in tlie adult, but these will 

 1)6 dealt with when describing the development of a colony. 



Nervow: System. — Dorsal to the pharynx is a cluster of cells 

 (Fig. 8, g.) of somewhat reticulated appearance. They coincide in 

 position with the ganglion figured by Vallentin/ and although I 

 was unable to detect the threads connecting with the marginal 

 nerve cells of the disc, it seems probable that this represents the 

 brain. In the Asplanchnadse the brain can be easily seen in a 

 specimen suitably killed and fixed with osmic acid. It there 

 appears as a large mass giving off threads in various directions, 

 and it is situated dorsal to the pharynx, as is the case in numer- 

 ous other species of rotifers. As L. striolata leads a sedentary 

 life, and the chief use of its sensory apparatus is to warn it to 

 retract into its tube, it would appear that a simpler nervous 

 organisation would suffice for it than for free swimming preda- 

 tory animals like the A<;pla7ichnadce. Sections gave no trace of 

 the eye spots. The ventral antennse (Fig. 2, ant.) were well 

 sliown in sections and exhibited some detail of structure I do 

 not remember to have seen mentioned. The section drawn (Fig. 

 14) shows a spherical cavity with the tuft of sette springing from 

 the inside and passing through a small perforation in the cuticle 

 (c.u.): the walls of the cavity rest upon a nerve ganglion (n.g.), 

 and from it runs a thread leading in the direction of the head. 

 I may here state that it is difficult to ti-ace the nerve threads, 

 muscles, and other structures passing up the neck, as the mastax 

 so fills the space that only a narrow ring is left where these 

 organs are so closely packed as to be indistinguishable. 



Muscular System. — Eight longitudinal muscles are seen in a 

 transverse section of the foot (Fig. 15, mu.) and extend almost 

 to its termination ; they appear to run the whole length of the 

 body and terminate in the trochal disc. No trace of circular 

 muscles could be seen. 



Reproductive System. — Tlie yolk gland (Fig. 3, y.g.) is con- 

 spicuous in the adult female. Apparently there is only a single 

 germarium situated towards the posterior end of the yolk gland 

 (Fig. 16, v.). Ova pass down the oviduct (Fig. 5, ov.) and are 

 extruded at an early stage and undergo development imbedded 

 in the matrix of the colony. Ordinary and " resting eggs " (Fig. 



3 Anatomy of Certain Rotifers. Mag:. Nat. Hist., ser. 6, No. 43, p. 47, pi. v., fig. 12. 



