1890.] ON THE ANATOMY OF PODICA SENEGALENSIS. 425 



species for comparison ; thej- include immature stages, but all are very 

 different from the species now described. As the immature C echi- 

 nipes closely resemble the adult, it is probable that even if the 

 specimen from which the above description is taken be not quite 

 mature, the adult would not differ greatly. 



EXPLANATION OF THE PLATES. 



Plate XXXVII. 



Fig. 1. Notaspis burrowsii, x50, p. 418. 



2. , first leg, xllO. 



3. , fourth leg, xllO. 



4. , pseudostigmatic organ, x300. 



6. aquatis, xSO, p. 419. 



6. EremcBus Jimhriatus, XlOO, p. 422. 



7. CeBcidus spatulifer, X 50, p. 423. 

 , claw, X 200. 



PL.vrE XXXVIII. 



Fig. 1. DanuBiis phakmglouhs, x50, p. 421. 



2. flwjdlifer, x(i5, p. 422. 



3. patclluides, x 70, p. 420. 



2. On the Anatomy of Podica senegalensis. By Frank E. 

 Beddard, M.A.J P.R.S.E., Prosector to the Society, 

 and Lecturer on Biology at Guy's Hospital. 



[Eeceived May 6, 1890.] 

 (Plate XXXIX.) 



As so little is known about the anatomy of the Heliornithklce and 

 as, in consequence of this, the opinions with regard to the systematic 

 position of the family are so diverse, I am particularly glad to be 

 able to offer to the Society a contribution towards the settlement 

 of this question. 



I am able to do this through the great kindness of Dr. Jentink, 

 who permitted me to dissect and study a fine example of the bird 

 well preserved in alcohol. Dr. Biittikofer, to whom, as the curator of 

 the Bird department of the Leiden Museum, I applied for assistance, 

 was good enough to mention my wants to Dr. Jentink, offering on 

 his own account to let me have the use of a rather imperfect skeleton 

 brought by him from Africa. To both these gentleman I desire here 

 to tender my hearty thanks. 



Although many families and genera of birds have not yet found 

 a definite resting-place in the system, the UeliornitJiidce have been 

 perhaps more tossed about from pillar to post of the ornithological 

 edifice than most. They have mainly oscillated between the Divers 

 and Grebes on the one hand, and the Bails on the other. 



On the wliolr, the ojmiion of ornithologists has been in favour 



