673 



A NEW ENDOPARASITIC COPEPOD: MORPHOLOGY 

 AND DEVELOPMENT. 



By H. Leighton Kesteven, D.Sc, Lecturer in Physiology, 

 Technical College, Sydnicy. 



(Plates Ixviii. Ixx.) 



Introduction. — The parasitic copepod herein described occurs, as 

 far as is yet known, only in Ptychodera australis Hill, and in the 

 genital ridges thereof. The Enteropneust has only been recorded 

 from the type-locality, that is, the coast of New South Wales, a 

 few miles north of Port Jackson. 



For my material, I have to thank Professor J. P. Hill. It com- 

 prises entire specimens and serial sections, some of the latter in situ 

 in the host. The fixation is exceedingly good in most of the speci- 

 mens, and the staining all that could be desired, so that, for any 

 imperfections in the description, I alone am responsible. 



This material was given me in 1905; the long delay which has 

 occurred has been due to want of detail of the structure of certain 

 of the appendages. After many fruitless trips in search of further 

 material, on the part of myself and friends, in desperation I dis- 

 mounted some of the whole specimens, and after treating them 

 with one per cent, aqueous solution of sodium hydroxide, obtained 

 from the clarified exoskeleton floating in glycerine the required 

 details; the pictures so obtained were checked by subsequently 

 cutting the exoskeleton along the length dorsally, so that it could 

 be flattened out, and examined with an oil immersion, so small and 

 flexible are the appendages that nothing short of such high magni- 

 fication gave one faith in one's observations. The appendages as 

 seen under the oil (Reichert, j\) were traced with the camera 

 lucida. 



U B I u s, gen. nov. 



A genus of Copepod crustaceans typified by U. hilli (postea), 

 closel}^ allied to the montoypical genus Ive Mayer(5), but differing 



