240 bulletin: museum of comparative zoology. 



Of the numerous British species, P. aurora Salter, P. hicksi Salter, 

 and P. forchhammeri Angelin have the glabella reaching on to the rim, 

 P. davidis is of the P. tessini type with the elongated terminal spines 

 of the pleura, as is also, presumably, P. bohemicus salopiensis Cobbold, 

 of which the thorax is not loiown. P. groomi Lapworth is of the P. 

 harlani type, P. harknessi Hicks agrees with the new species in the 

 presence of a furrow between the glabella and rim, but the eye lobes 

 are much longer and more narrow, and the glabella is narrower and 

 retains the first pair of furrows. P. intermcdius Cobbold is quite 

 similar in form of glabella, groove and rim, to P. haywardi, but the 

 palpebral lobes are too long and reach both the neck ring and the 

 glabella. The Paradoxides rugulosus Hawle and Corda, Cobbold, also 

 has the long eye lobes and the first pair of glabellar furrows, and, 

 moreover, differs from the true rugulosus in lacking the furrow which 

 should separate the glabella from the rim. 



Turning now to the Scandinavian species, we find that P. forch- 

 hammeri Angelin, P. hicksi palpebrosus Linnarsson, P. oelandicus 

 Sjogren, and P. tumidus Angelin all have the glabella reaching the rim, 

 and most of them have other features in which they differ strikingly 

 from P. haywardi, while P. affinis Angelin, and P. tessini Brongniart 

 and its varieties of course have the long terminal spines on the pleura. 

 P. tuberculatus Angelin is known only from a fragment which has a 

 large tubercle on the fixed cheek opposite the basal lobes of the glabella. 

 P. brachyrhachis Linnarsson appears to be a rimless species with four 

 pairs of glabellar furrows, and so comparable to P. harlani, while P. 

 aculeatus is based on a very immature specimen. There is, therefore, 

 no Scandinavian species very closely allied to P. haywardi. 



Of the Bohemian species, P. bohemicus (Boeck) is quickly eliminated 

 because in the adult the glabella reaches the rim and the terminal 

 segments of the pleura are elongated. P. desiderahis is probably not a 

 Paradoxides, but possibly an Albertella, and P. ciycctans also is doubt- 

 fully a Paradoxides. P. imperialis is known only from a fragment of 

 the thorax, while P. inflatus Corda, P. pusillus Barrande, and P. 

 orphanus Barrande are evidently based on very immature specimens. 

 P. spinosus and P. rotundatus Barrande both have glabellas which 

 in the adult touch the anterior rim and retain all four pairs of furrows 

 in most cases. P. rugulosus and P. sacheri both have the groove in 

 front of the glabella, but P. rugulosus has very long eye lobes, touching 

 the glabella and occipital ring, while P. sacheri has very short diagonal 

 furrows and very curving spines on the thorax. P. lyelli has a long 

 narrow glabella which touches the marginal rim. 



