RAYMOND: NOTES ON THE ONTOGENY OF PAIi.\DOXIDES. 239 



Remarks. 



As may be seen by the following quotation, the specimens here 

 separated as a new species have not escaped observation. Dr. Wal- 

 cott (Loc. cit., p. 46), in discussing the broad and narrow forms of P. 

 harlani says : — " In the head the greatest variation is seen in the contour 

 of the frontal margin, and the gradual development of the frontal 

 limb and rim. On the smallest specimens the frontal limb is very 

 short and more or less rounded. With the increase in size, the space 

 between the glabella and the marginal rim increases in width, and the 

 latter broadens and flattens out." It is not the narrow form of P. 

 harlani as described by Walcott and Grabau which I am separating 

 as a new species, but the form with the narrow brim and raised, 

 striated rim. Judging from the above quotation, this form has been 

 placed as the young of the narrow form of /'. harlani. As has been 

 shown under the description of P. harlani above, material recently 

 collected shows that the young of P. harlani had a broad flat rimless 

 brim, similar to that of the adult, so that the rimmed forms can not 

 be referred to that species. 



Comparison with other Species. 



Paradoxides hay war di is a much more normal type of Paradoxides 

 than P. harlani, and it is therefore comparable to a far greater number 

 of species. From P. harlani itself, it differs, as has already been 

 pointed out, in having an angular instead of a rounded frontal margin, 

 and in having a narrow brim and thickened rim on the front of the 

 cranidium, in the absence of the anterior pair of glabellar furrows, and 

 probably in the wider furrows and narrower spines on the pleura of 

 the thorax. It resembles P. etcminicus Matthew more closely than 

 any other American form, but differs from that species in having 

 shorter eyes, the lobes of which do not touch the glabella or neck ring, 

 in lacking the anterior pair of glabellar furrows, and in having a wider 

 groove separating the glabella from the rim. Most of these same dif- 

 ferences and others obtain between P. abenacus Matthew, P. acadius 

 Matthew, P. micrnac Hartt, P. lamellatus Hartt, and P. haywardi. 

 P. regina Matthew and P. hennetti Salter appear to have the wide 

 margin of P. harlani; and of Billings's two Newfoundland species, 

 P. tenellus seems to be based on immature specimens, and P. dccorus 

 is not well known. 



