STAKES: THE CHAEACTERS OF ATELAXIA. 21 



geals are present ; a styloid toothless pair on the first arches, and three tooth- 

 bearing pairs behind them. The lower pharyngeals are nearly obsolete, toothless, 

 and covered with skin, and bordering the short slit between them and the fourth 

 arch. 



The clavicle is an S-shaped bone bending forward toward the cranium above 

 and backward around the hypocoracoid below. The supraclavicle is joined to 

 the lower and inner surface of the upper limb rather than to the outer sur- 

 face. It is a long, slender, fibrous bone reaching far forward. To it in turn is 

 joined the simple posttemporal, which resembles the supraclavicle in shape and 

 texture, though it is shorter. The posttemporal joins the small epiotic process 

 rather loosely, and has no other attachment to the cranium. A long slender ray 

 of bone attached to the upper inner edge of the clavicle and extending backward 

 represents the postclavicle. 



The other elements of the shoulder girdle are poorly ossified. Two delicate 

 thin plates, more cartilage than bone, represent the hypercoracoid and hypocora- 

 coid. The latter arches away from the clavicle and rejoins it at its lower end 

 in the typical way ; the former bears a small foramen near its border next to the 

 clavicle. Four actinosts are present in a horizontal row ; the suture between the 

 coracoid elements is opposite the third one. They are delicate broad plates as 

 poorly ossified as the coracoid elements. 



The caudal portion of the vertebral column is in no way differentiated from 

 the thoracic ; the vertebrae number fifty-three. Each vertebra consists of a cen- 

 trum, somewhat smaller at the middle, and having a pair of thin longitudinal ridges 

 above and below representing open neural and haemal canals, but there are other- 

 wise no spines or processes of any sort, and no ribs are present. The last verte- 

 bra expands posteriorly into a narrow hypural plate from the lower half of which 

 the long filamentous process projects backward, and from the upper edge the small 

 caudal rays project upward. The long caudal process is formed from the lower 

 three caudal rays, which are very much stronger than the upper rays. 



The interneural rays are cartilaginous with soft fibres of bone intermingled. 

 They are T-shaped with the posterior part of the cross limbs much longer than 

 the anterior, and all connected so that a continuous band of fibrous bone is formed 

 along the back. A short distance in front of the shaft of each interneural at the 

 union of the cross limbs is situated the dorsal ray. The band formed by the cross 

 limbs is of the sort shown by Parker (1. c.) in his picture of Regalecus, though it 

 is straight not V-shaped between the dorsal rays. The shaft of each interneural 

 is long and slender, and runs from the back to the vertebral column, where it is 

 in contact with the upper surface of the vertebra ; two of them to each vertebra. 

 There are no interhaemals or other evidence of an anal fin. The dorsal rays show- 

 no trace of cross articulations. 



The viscera was so disintegrated that little could be made out. The intestine is 

 long and straight, and without pyloric caeca. An air bladder was apparently pres- 

 ent, not as a loose sack, but as a membranous septum dividing the upper part of 

 the abdominal cavity from the lower. No air duct could be made out from this 

 to the oesophagus. 



