200 NOTES AND MEMORANDA. 



L. Tethyce is furnished with a very loug cyhndrical stem, 

 terminating below in an enlarged^ foot-like extremity, in which 

 a pedal gland is lodged. It is said to be nearly related to 

 L. Raja, Schmidt. 



We require a much more minute and precise description of 

 these species. 



The interest of the paper, however, lies in its studies of 

 structure and development. 



In the first place, the author has determined the nervous 

 system of Loxosoma which had escaped both Nitsche and Vogt, 

 and traced its connections with the organs of sense described by 

 the latter author. The only representative of a central nervous 

 system is a small ganglion placed in the middle of the body 

 above the stomach, between the extremity of the oesophagus and 

 the commencement of the intestine, and more on the dorsal 

 than the ventral side. In the adult it is extremely difficult to 

 make it out, as it is concealed by the reproductive organs, but it 

 is easily detected in the young polypide. The ganglion is a 

 small ovoid body, which gives off nerves in many directions. 

 The smaller nerves the author was unable to follow ; the largest 

 pass off on both sides of the ganglion towards the dorsal portion 

 of the body. Each of them gives off many lateral branches, 

 and in the middle of its course presents a small thickening 

 composed entirely of nervous cellules. As they approach the 

 surface of the body, the nerves become thinner at first and then 

 swell out into small pyriform knots, which are enclosed in tuber- 

 cular elevations of the integument. These tubercles, placed on 

 the dorsal surface, on each side of the longitudinal axis of the 

 body, are the organs of sense. Their structure is identical with 

 that of the *' antennae '^ of the Rotifera. They consist of small 

 tegumentary swellings the cavity of M'hich is filled by the 

 nervous matter, bearing on the summit a cluster of fixed setse, 

 which are united at their base to the nerve-knot. 



This description of the structure of the tactile organ differs 

 from that of Vogt, who represents the papilla as occupied by 

 a number of conical cells. 



The plan of the nervous system as just described is similar to 

 that which has been demonstrated by Kitsche for RedicelUna. 



Another organ is described by Salensky, which has escaped the 

 notice of previous observers. It is composed of a pair of multi- 

 cellular glands, having the form of two bunches of grapes. 

 They are lodged in the parenchyma of the body on each side of 

 the intestine. Each gland consists of eight cells borne or 

 pedicles ; the cells are ovoid and composed of a delicate membrane 

 and transparent protoplasm. All the pedicles of the cluster 



