RAYMOND: NOTES ON THE ONTOGENY OF PARADOXIDES. 231 
study these specimens, I supposed them to be the young of that 
species. That they do not belong to that species is, however, shown 
convincingly by the eyes. The adult of P. rugulosus has the palpebral 
lobes touching the glabella at their anterior ends and reaching the 
occipital furrow behind, while in the adult of P. spinosus the eye is 
much shorter, and does not reach either the glabella or the occipital 
furrow. Barrande has figured (Loc. cit., pl. 12, fig. 7) a specimen of 
P. spinosus with a glabella 4.5 mm. long in which the eyes have the 
same position as in the adult, while in the Museum series, specimens 
this size have the rugulosus type of long eyes. The thorax of P. 
pusillus is of the spinosus rather than the rugulosus type, but that is a 
character which might change readily during growth from a size of 
4 mm. up to the size of the adult P. rugulosus. It is, however, possible 
that the young of the two species would be, in the earliest stages, in- 
distinguishable. 
YouNG SPECIMENS OF PARADOXIDES. 
Bohemia. 
Hydrocephalus cavens Barrande and Paradoxides inflatus Corda make 
a short series showing the early growth stages of some as yet unidenti- 
fied species. Barrande figures nine stages in the growth of H. carens, 
the smallest specimen being 2 mm. long and the largest 4 mm. The 
thorax and pygidium together show three segments in the smallest 
Fig. 2. Fig. 3. 
Fig. 2— Hydrocephalus carens Barrande. After Barrande. This series shows 
two stages in the development. Compare with Plate, fig. 3. 
Fig. 3.— Paradozides inflatus Corda. After Barrande. 
and fifteen in the largest. The glabella is almost circular and shows 
no glabellar furrows in the first four stages described, and only No. 4 
is present in the last five. Intergenal spines are present on all, and 
on specimens 6-9 the first two segments of the thorax have terminal 
