ANCKHUS. 170 
In 1864, M. Hesse published his detailed “ Mémoire 
sur les Pranizes et les Ancées,” 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 métamorphose 
de la larve en Ancée.” 
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 larve in 
fig. 30 correspond only with fig. 11. This latter cir- 
cumstance probably may be only the result of the artist’s 
