raymoxd: notes on the ontockav of paradoxides. 233 



specimen, only 1 1 mm. long, should be so like the adult. The chief 

 differences are that the eyes are slightly longer, the genal spines arise 

 further forward on the head, and the terminal spines of the second 

 thoracic segment are much longer. These terminal spines of the 

 second segment seem the most persistent of the juvenile characters, 

 and as has already been stated, all the Bohemian species have some 

 remnant of these spines in the adult stage. 



The youngest specimen of P. hohemicus yet seen is that figured by 

 Barrande {Loc. cit., pi. 10, fig. 25). It is 14 mm. long, not including 

 spines, and exhibits only two youthful characteristics. The eyes are 

 long, and the terminal spines of the second thoracic segment are 

 greatly prolonged. The glabella shows only two furrows (Nos. 3 and 4) 

 the same as in the adult. 



Outside Bohemia young Paradoxides are evidently exceedingly 

 rare and have been figured only incidentally. Nothing except a few 

 cranidia seems to have been found. 



Scandinavia. 



The "youngest Scandinavian specimen known is that figured by 

 Linnarsson as the t^'pe of his species P. aculeatus. This is a cranidium 

 slightlv less than 2 mm. long from the Paradoxides oelandicus zone 

 of Borgholm. There is a relatively wide brim in front of the glabella, 

 the palpebral lobes extend from the second glabellar lobes to the pos- 

 terior margin, intergenal spines are present, the glabella is long and 

 narrow, expands slightly forward and has four pairs of glabellar fur- 

 rows. It resembles a young Paradoxides more than Hydrocephalus 

 saturnoides does, as the glabella is of a more normal shape. This 

 specimen ^ is probably the young of either P. sjogreni or P. oelandicus, 

 more likely of the former, as Linnarsson figures another small crani- 

 dium 5.5 mm. long which he refers to that species, though with doubt. 

 This latter specimen also has a wide brim and four pairs of furrows. 

 The adults of both P. sjogreni and P. oelandicus have a narrow border, 

 and the glabella almost touches the rim. 



Great Britain. 



Salter figures (Quart, journ. geol. soc, 1869, 25, pi. 3, fig. 8-10) 

 three young specimens of Paradoxides hicksi. These specimens are 



I Lindstroem considers this the young of P. oelandicus. K. Svensk. vet.-akad. 

 Handl., 1901, 34, no. 8, p. 17. 



