RAYMOND : NOTES ON THE ONTOGENY OF PARADOXIDES. 



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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., pi. 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. 

 pu-sillu-s is of the sj/inosus rather than the rugulusus 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 carens 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 //. 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'BQ.TTdLXide. After Barrande. This series shows 



two stages in the development. Compare with Plato, fig. 3. 

 Fig. 3. — - Paradoxides 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 



