626 REPORT OF NATIONAL MUSEUM, 1898. 



quite as long as the maxillary braucli, and is on a superior plane, being 

 in close contact with its mate on the middle line, and forming with the 

 maxillarj^ plate a half tube opening inward. Pterygoids not very 

 wide, gradually narrowing to the posterior rod, which is oi)enly grooved 

 on the inner side. The basipterygoid processes overlap the entire width 

 of the internal face. Ectopterygoid reaching maxillary and jugal, but 

 not i^alatine; little deflected posteriorly. Presphenoid not ossified; 

 sphenoid distinguished from basioccipital by suture. Latter with sub- 

 conic descending lateral processes, which inclose a deep fossa on the 

 external side. Postoptic small, simple, crescentic. Petrosal extended 

 well in advance of semicircular canal above; subforaminal portion still 

 more produced, bounding a down looking open groove. Parietal send- 

 ing downward a rather elongate process in front of petrosal. Ej)ij)tery- 

 goid originating opposite basipterygoid below, and resting above on 

 the descending process of the parietal and the anterior margin of the 

 petrosal. Occipital condyle tripartite. 



Meckel's cartilage exposed from the anteriorly placed splenial 

 foramen. Coronoid a little produced anteriorly on external face of 

 ramus, not at all posteriorly. Surangular and articular distinct; angle 

 flat, rounded, not produced or angular inward. Dentary produced as 

 far posteriorly as coronoid; si)lenial rather elongate (forming the 

 inferior border of Meckel's groove in E. ohsoletus). 



]n the hyoid system, U. quinquelineatus j)reseuts a short second cerato- 

 branchial. The first ceratobranchial has a cartihiginous terminal seg- 

 ment, as has also the ceratohyal. The latter is of moderate length, is 

 without expansions, and is articulated with the extremity of the rather 

 short hypobranchial. There is a large free epibranchial, which com- 

 mences near the free extremity of the second ceratobranchial, and curv- 

 ing backward, outward and then forward, terminates nearly opposite 

 the middle of the ceratohyal. 



The cervical intercentra in the U. ohsoletus number four, and those of 

 the U. qiiinqtielinetus three, posterior to that of the atlas. There is no 

 zygosphene. The caudal diapophyses are well developed at the base 

 of the series, and are split lengthwise at the middle and distal part 

 of the series by the segmentation of the vertebrte. Neural spine 

 single at posterior extremity of neural arch. 



The suprascapula is expanded anteroposteriorly, and the scapula is 

 rather elongate. The latter has no proscapula, while the coronoid has 

 one emarginatiou. The sternum has a small fontanelle jjosteriorly 

 placed. There are three costal articulations and a xiphoid rod with two 

 ribs. The latter is in close apposition to its mate, and is expanded 

 outward at the junction of the first hfemapophysis. 



The ilium has no angulns cristw, and the acetabulum is entire. The 

 pubes converge at a subacute angle, and the small pectineal process is 

 nearer the proximal extremity, and is turned downward. The ischia 

 are subtransverse, and i)reseut a wide emarginatiou posteriorly, since 

 the processus tuherosus is near the acetabulum. 



