628 Transactions of (he Society. 



encircle the body at regular distances from the side humps down- 

 wards. 



There are also fine muscular threads which contract the dorsal 

 and lateral humps, but these I have already described. 



There are five known species oi Asplanchna, viz. A. Bright wellii, 

 A. Sieboldii, A. j^riodonta, A. Ehheshornii, A. Bowesii. The last, 

 A. Bowesii, was described by Gosse, but so very briefly that 

 I prefer at present to pass it over. The other four are related to 



one another as follows. 



* 



With serrated Jaws, round ovary, small spherical contractile 

 vesicle, vibratile tags in a cluster on a twisted thread. 



A. ijriodonta. 



** 



With branched jaws, horseshoe-shaped ovary, large-lobed con- 

 tractile vesicle, vibratile tags in a row on a long straight thread, 

 -r, 1 .,1 ,1 I Male humpless . . A. BriqhtiveUiL 



Female without humps . . \^^^^^ ,,-ith humps A. Sieholdii. 



Female with humps . . . . Male with humps A. Ehheshoi'nii. 



