BRITISH FOSSILS. 



Decade XI. Plate X. 



PARADOX IDES DAVIDIS. 



[Genus PARADOXIDES. (Sub-kingdom Articulata. Class Crustacea. Order 

 Trilobita. Family Olenidse.) Elongate, of many segments, with a broad head and 

 spinous head-angles, often greatly extended. Glabella widely clavate, with the lower 

 furrows complete across. Labrum soldered to the hypostome. Body rings flattened, 

 17 to 20 in number, produced into recurved spines. Tail small, of few segments. Range, 

 primordial zone only.] 



Diagnosis. P. sesquipedalis et ultra, maxirmis, glabella parum cla- 

 vata, genis latiori, sulcis duohus solum perfectis, reliquis obsoletis. Oculi 

 antrorsum positi. Thorax articulis 19, axe lata. Pleurce suhrectcR^ 

 apicibus recurvis ; anticis brevissimis abrupte flexis^ ultimis longissimis, fere 

 parallelis, Cauda truncata, axi obscuro 2-3 aymtilato ; gladiis latera- 

 libus longissimis. 



Synonyms. Paradoxides Davidis, Salter (1863), Quart. Journ. Geol. 

 Soc. (1864), vol. XIX., p. 275, woodcut, and XX., pi. 13, fig. 1-3. 



The genus Paradoxides, from its bulk, has necessarily attracted 

 attention from the earliest times in which fossils have been observed 

 and collected. Linnaeus figured it, from Sweden, and Count Kinsky 

 from Bohemia, in the 18th century, and the Entomostracites para- 

 doxissimus was still the name under which Wahlenberg noticed it 

 in his resume of the Swedish Trilobites in 1821. Brongniart added 

 to the typical form several species afterwards known as Olenus by 

 Dalman, who did no more than uselessly change the name of the 

 whole genus. And while the species were distinguished by subse- 

 quent observers, the new name Olenus seems to have been adopted 

 till Bronn, in 1835, restored that which Brongniart had imposed. 

 Zenker, in 1833, had suggested a division of this large genus, making 

 the great Paradoxides the type of Olenus, and so reversing the 

 original nomenclature. But Emmrich's essay did not second this 

 idea, and it was left for Goldfuss, in his systematic review of the 

 group (Jahrbuch, vol. v., 1843), to give their correct definition to 

 these two genera, which have since been generally adopted. 



The broad club-shaped glabella, large head spines, and numerous 



[XI. X.] 11 K 



