"240 Transactions of the Society. 



rounded projection on the frontal part of the lorica, stippled round 

 the ed^e, and having ten " bosses " round the margin ; previously 

 found in India and Australia. 



The giant Pterodina is evidently Pt. trilobata of Shephard,* a 

 very fine rotifer, the internal organisation of which had not previously 

 been recorded. Mr. J. Shephard gives the size of the lorica as ^^ in. 

 long by 5^ in. wide, which is either a mistake, or else a remarkably 

 small specimen ; nor does this size agree with his drawing, which is 

 said to be magnified 315 times. The shape of the lorica of the Natal 

 specimen agrees perfectly with Shephard's figure, and as size alone is 

 not a sufficient reason for a new species, I have no hesitation in identi- 

 fying this Natal specimen with Shephard's species. 



Mr. F. E. Dixon-Nuttall, with his usual skill.has made two excellent 

 drawings of this animal from the mounted specimen sent from Natal, 

 which are reproduced in the accompanying plate (plate VI.) The 

 figures represent the dorsal and ventral aspect of two different animals 

 found in the same slide. The size of the mounted specimens sent by 

 Mr. Kirkman varies slightly between ^ in. and -fy in- (32 o fi and 

 350 /i), which, however, is nearly double the size of the largest Ptero- 

 dina patina. The lorica is quite flat, almost circular in shape, trans- 

 parent, and finely and evenly stippled. The frontal edge shows three 

 more or less pronounced rounded lobes, while the mental edge has a 

 V-shaped sulcus ; round the edge there are ten bosses at regular inter- 

 vals, but there is no " milling " round the outer edge. The animal 

 being so large, flat, and transparent, displays its internal organisation 

 better than any other species of the genus. The head is of the usual 

 form, with two red eyes containing a minute spherical crystalline lens; 

 the dorsal antenna above the mastax and the two lateral antennas in 

 their usual position on the shoulders are readily found. The mastax 

 is of usual shape and structure. At the junction of the short oeso- 

 phagus with the stomach arise a pair of large gastric glands which 

 spread right and left in numerous irregular tubular branches to Dear 

 the margin of the lorica, the branching being different in every in- 

 dividual ; near the middle of each gland there is a large nucleus, as if 

 it consisted of a single cell. At the base of the mastax there are four 

 or five very short tubular glands, which may be considered salivary 

 glands, similar to those found in all other Pterodinse. In addition to 

 these there are a pair of large salivary glands of finer structure arising 

 above the mastax, and spreading right and left parallel with but 

 above the gastric glands, and in much finer granular threads, while 

 one broader band crosses the gastric glands, and runs backwards a 

 short distance, parallel with the retractor muscles. The development 

 of the oesophageal and gastric glands is very striking in this species, 

 and quite unlike that of any other known Pterodina. The stomach 

 is fairly large, saccate, and is made up of large nucleated cells. The 



* H. H. Anderson and J. Shephard, Notes on Victoria:! Rotifers, Proc. Roy. Soo- 

 Victoria, 1892, pp. 69-80 (2 pis.). 



