ANCEUS. 175 



In 1864, M. Hesse published his detailed " Memoire 

 sur les Pranizes et les Ancees," 4to, Paris, with a vast 

 amount of supplemental materials, from which he de- 

 duced the following results : 



1. That Praniza is only a " phase de la metamorphose 

 de la larve en Ancee." 



2. That at the end of the larval state, in which 

 sexual differences are not perceivable, these Crustacea 

 are transformed into males and females. 



3. That the male and female are completely distinct 

 in form, and that the young state, or Praniza form, is so 

 unlike that of the two sexes, that it may be mistaken 

 for a different species. 



4. That the female of Anceus had hitherto been totally 

 unknown . 



5. That during their larva, or Praniza form, they are 

 parasitic on fishes, with a mouth fitted for sucking blood, 

 and that after quitting the fishes and assuming the Anceus 

 form, they live " a terre ' with a greatly modified form 

 of the mouth, furnished with formidable mandibles. 



6. That the Anceus form is that of their final meta- 

 morphosis. 



In contrasting these results with the plates which 

 accompany M. Hesse's memoir, we cannot but express 

 our conviction that his conclusions are far from being 

 borne out by his own recorded observations. 



If the student will but turn to M. Hesse's elaborate 

 memoir, we think that we shall be able even thence to 

 demonstrate the correctness of our own conclusions on 

 these anomalous animals. In plate 1, the figures 9 and 

 11 nearly correspond in the natural size of the objects, 

 but materially differ in form ; whereas all the larvae in 

 fig. 30 correspond only with fig. 1 1 . This latter cir- 

 cumstance probably may be only the result of the artist's 



