448 The Systema'ic Position of Stylophorns caudatus. 



inserted in the ligament between the coracoids and sometimes 

 directly articulated with them." 



Stylophorus agrees with the Tseniosomi and differs from 

 the other Allotriognathi in the following characters : — 



" Body elongate. Skeleton feebly ossified; ribs feeble or 

 absent; lower pharyngeals reduced, toothless. No occipital 

 crest. Post-temporal simple ; pectoral pterygials plate-like, 

 two or three of them in contact with the coracoid. Fins 

 composed of simple flexible non-articulated rays ; dorsal fiu 

 very long ; anal short or absent * ". 



Stylophorus differs from the Teeniosomi in several respects, 

 of which the moBt important are the moderately compressed 

 body, which is eel-shaped rather than ribbon-shaped; the 

 very long lower jaw and backwardly directed suspensorium, 

 correlated with which is the reduction of the pterygo-palatine 

 arcade to a single small pterygoid element and the shifting 

 of the attachment of the branchiostegals from the lower to 

 the upper edge of the cerato-hyal ; the cranium more de- 

 pressed posteriorly, with the epiotics separated by th • supra- 

 occipital t» the frontals united by suture throughout their 

 length, the orbito-sphenoid absent and the vomer very small, 

 in position corresponding to the posterior extremity of the 

 vomer in the Tseniosomi ; the absence of neural and haemal 

 spines and the fewer vertebra?, 53 in number. 



A special resemblance to Trachypterus is shown in the 

 structure of the caudal fin, which is divided into a lower 

 portion with horizontal rays and an upper portion with the 

 rays directed upwards. 



I take this opportunity of calling attention to an excellent 

 account of the anatomy of Trachypterus arcticus by Mr. A. 

 Meek ('Studies Mus. Zool. Dundee/ i. 1890, pp. 55-77, 

 pis. i. & ii.) which I had previously overlooked and which 

 JDr. Starks also does not seem to have known. 



Dr. Starks is to be congratulated on having given us so 

 complete and careful an account of the anatomy of this 

 peculiar type, but his method of presenting his results is open 

 to criticism. His diagnosis of the suborder Atelaxia does not 

 give ai y clue as to its position in the system, and consists 

 almost exclusively of those features which distinguish it from 

 the Tseniosomi, whilst those characters which the two groups 

 have in common are regarded as of minor importance and are 



* The anal fin is said to be absent in Stylophorus, but Stark's figure 

 shows an anal fin with 12 rays in the middle of the length of the tish ; 

 this seems to be an instance of " artistic ticensi 



f The meeting of the epiotics behind the supraoccipital is often due to 

 the elevation of the posterior part of the cranium. 



