286 RESEARCH IN CHINA. 



Asaphus blackwelderi Weller (plate 26, figs. 21, 22). 



1907. Asaphus blackwelderi Weller, Proc. U. S. Nat. Mus., vol. xxxn, p. 560. 



Cranidium comparatively short and broad with the axis obsolete, obtusely 

 angular in front, the palpebral lobes large and prominent, their anterior margins 

 nearly opposite the middle point of the head ; in front of the eyes the lateral margins 

 diverge gradually to a point nearly half-way to the anterior margin, where they are 

 rather broadly rounded and then converge somewhat abruptly to the anterior 

 extremitv; back of the eyes the lateral margins diverge rapidly and curve backward 

 to the posterior margin, the width of the cranidium along its posterior margin being 

 considerably greater than the distance between the eyes. The occipital furrow and 

 segment are faintly developed. A slight median tubercle is situated at a point about 

 half-way between the line joining the posterior extremities of the eyes and the pos- 

 terior margin, aside from which the surface of the cranidium is apparently smooth. 



A free cheek is associated with this cranidium and possibly belongs to the same 

 species ; its lateral region is differentiated as a rounded marginal border, and its genal 

 angle is produced into a rather strong genal spine. 



The dimensions of the cranidium described are: length 8 mm., width between 

 the eyes 6 mm., width along posterior margin 7.5 mm. 



The outline of the cranidium upon which this species is established somewhat 

 closely resembles that of .4. expansus Dalman, the typical species of the genus, and 

 both species are marked by a similar small median tubercle near the posterior mar- 

 gin. This Chinese species may be distinguished from its European ally, however, 

 on account of the obsolete glabella. If the free cheek which occurs with A. black- 

 welderi really belongs to the species, this also will serve to distinguish the two forms 

 by reason of its strongly developed genal spine, these spines being absent from the 

 European species. This cranidium should possibly be associated with one of the 

 pygidia described in the present paper, possibly with the one which has been com- 

 pared with A . expansus, although the cranidium does not occur in the same locality 

 with these pygidia in the collections studied. 



Asaphus taningensis Weller (plate 26, figs. 19, 20). 



1907. Asaphus taningensis Weller, Proc. U. S. Nat. Mus., vol. xxxil, p. 561. 



Cranidium rather long and slender, with the axis nearly obsolete ; the palpebral 

 lobes apparently rather small, situated back of the mid-length of the head. In front 

 of the eyes the lateral margins of the cranidium describe the two sides of an ovate 

 curve, gently diverging from the anterior extremities of the eyes, then broadly 

 rounding and converging abruptly in front to the obtusely subangular anterior 

 extremity; back of the eyes the lateral margins diverge abruptly with a gently con- 

 vex curve to the posterior margin. Anteriorly the surface of cranidium is somewhat 

 flattened to form an indistinct anterior limb. Occipital furrow and segment nearly 

 obsolete. A faint median tubercle is situated on the median line of the head about 

 half-way between the line joining the posterior extremities of the eyes and the pos- 

 terior margin, but aside from this the surface of the cranidium is smooth. 



The dimensions of the type specimen are : length of cranidium 1 1 mm., width at 

 posterior margin 11.5 mm., width between the eyes 7 mm. 



This species is known only from the cranidium and it is of course possible that 

 it should be correlated with some of the species here described from the pygidium 

 alone. The only one of these pygidia, however, which is recognized from exactly 

 the same locality as this species is A. lams, which is such a short form that it is not 

 at all likely to be a portion of the same species as this elongate cranidium. The 

 species should perhaps be referred to the genus Megalaspis rather than Asaphus, 

 but this can not be determined from such incomplete material. 



