8 ART. 4.— BASHFORD DEAN. 



element, unique in an adult chimaeroid, appears on both sides of the 

 specimen dissected. 1} If we accept this important character as a nor- 

 mal one it is remarkable that the skull differs in further regards so 

 little from the well known conditions in the other Chimaeroids. For, 

 if we except the great size and shape of the upper median (rostral) 

 cartilage there remains little to distinguish " Harriotta " from Callo- 

 rhynchus. The contour of the cranium is closely similar, as is also the 

 proportional size of the orbits, and the position of the foramina of the 

 nerves. Referring again to the palato-quadrate element I note that 

 this is most distinctly marked out at its hinder border, as indicated in 

 the figure. I found however by slicing the cartilage in this region 

 that the separateness of the element is in a measure deceptive, for it is 

 superficial only. On the other hand, in the region of the anterior rim 

 of the orbit the line of suture can be followed deeply into the cartilage. 

 The striking feature in the mouth of this form is in the beak like deve- 

 lopment of the dental plates, in this regard quite unlike any Chimae- 

 roid described, for the plates themselves are reduced to an almost horn 

 like texture, losing the calcified tritoral points, so characteristic of the 

 entire group. And their edges are sectorial, narrowing away beak 

 fashion from their surface of origin. The appearance of the mandibu- 

 lar plates is given in Figs. 6, 6a. The " maxillary " plates are pro- 

 portioned larger and narrower than in other recent chimaeroids, over 

 three times as long as wide ; and there is thus a narrower band of pulp 

 from which the plate takes its origin: The " pre-maxillary " plates 

 are also constricted : instead of becoming opposed to one another in 



1) In the specimen in the museum of Columbia University, which I have had the op- 

 portunity of examining since the above was written, no trace of this suture occurs on either 

 side ! Accordingly, in the absence of further data, I am led ttrbelieve that the suturai con- 

 dition in the former specimen is exceptional. For. upon examination of a series of preparations 

 of the suturai region on Chimiera colliei, I have found in a single specimen, nearly full grown, 

 a male, that a distinct line of union is indicated. In this instance, however, the line is not as 

 distinct as in the above described specimen. 



