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126 MR. E. PHELPS ALUS. JUN., OX 



the dorsal surface of the palatoquadrate, and it is also eitlier 

 attached to, or related to. ligamentous or fibrous tissues which 

 are attached to the chondocranium in the nasal region ; and 

 these are probably universal conditions in these fishes. 



In Ckimcera Hubrecht (1877) describes five cartilages that 

 are called by him nasal cartilages, and four that are called 

 labials, the nasal cartilages being designated by the letters 

 f, 9, h m i ail( ? the labial cartilages by the letters a, c, d, e. 

 The letter n is used by Hubrecht to designate a process of the 

 cartilage k, this cartilage accordingly sometimes being referred 

 to as the cartilage kit. 



The cartilage k, with its large process n, is called by Hubrecht 

 -the Nasenmusehel, and as it certainly represents some part of 

 the ala nasalis of the Plagiostomi, ifc may be referred to as that 

 cartilage. It encircles the antero-mesial or so-called ingress 

 nasal aperture, and T have recently fully described it in this 

 fish (Allis, 1917?>). 



The cartilage shown in figure 4 (PI. II.), is a small and irre- 

 gular plate of cartilage which lies in the mucous tissues along 

 the lateral edge of the process n of the ala nasalis, and it extends 

 from that process to the inner surface of the cartilage fg. It 

 bounds the dorso-mesial edge of the postero-lateral nasal aper- 

 ture, and is attached both to the process n and the cartilage fg 

 by connective or fibrous tissues, its point of attachment to the 

 latter cartilage lying immediately beyond the base of the nasal- 

 fold process of that cartilage, to be described immediately below. 



The cartilage m is a thin, flat, curved, triangular cartilage 

 which is attached by its pointed mesial end to the dorso-mesial 

 surface of the ala nasalis (cartilage kn) near its external edge, 

 and from there extends ventro-latero-posteriorly in the nasal 

 portion of the naso-labial fold. A small nodule of cartilage 

 may be found attached to its latero- posterior edge. 



The cartilages/' and g, said by Hubrecht to be found separate 

 in Callorhynchus, are fused in Chrmmra, to form a single 

 piece called by Hubrecht both a, Lippenknorpeltrager and a 

 Nasenflugelknorpel. The two parts f and g differ slightly in 

 coloration and appearance, suggesting that they are of inde- 

 pendent oiigin, the part g being a flat plate-like superficial 

 cartilage, and the part f a. stout rounded and curved rod, which 

 arises from the ventro-posterior end of the plate-like portion 

 of the cartilage and may be called the pedicel of the entire 

 cartilage. The plate-like portion of the cartilage lies, in the 

 posterior half of its length, in a, nearly horizontal position 

 along the outer edge of the nasal capsule. Its dorso-anterior 

 half turns dorso-anteriorly across the outer edge of the nasal 

 capsule, and there lies on the outer surface of that capsule, 

 passing latero-posterior to the lateral rostral process and being 

 strongly but flexibly attached to that process by ligamentous 

 tissues. Approximately at the point where the process turns 

 dorso anteriorly, there is a prominent eminence on its internal 



