6n certain chossoptervgians. l27i 



Stensio, E. A:soN. 1918 a. Zur Kenntnis des Devons mid des 

 Kulms an der Klaas Billenbay, &'pitzbergen. Upsala, 

 Geo]. Inst. Bull. vol. xvi. 



. 1918 6, Notes on a Orossopterygian Fisli from the Upper 



Devonian of Spitzbergen. Upsala, Gaol. Inst. Bidl. 

 vol. xvi. 



. 1921. Triassic Fishes from Spitzbergen. Part I. Vienna. 



■. 1922 «. Tiber zwei OoBlocanthiden aus dem Oberdevon 



von Wildungen. Palseontologische Zeitschr., Bd. iv. 



. 1922 6. Triassic Fishes from Spitzbergen. Part II. (In 



manuscript.) 



SwiNNERTON, H. H. 1902. A Contribution to the Morphology 

 of the Teleostean Hea,d Skeleton, based upon a study of 

 the Three-spined Stickleback (^Gasterosteus acideatus). 

 Quart. Journ. Micr. Sci., New Ser. vol. xlv. 



Watson, D. M. S. 1921. On the Coelacanth Fish. Ann. & Mag. 

 Nat Hist., ser. 9, vol. viii. 



Woodward, A. S. 1891. The Devonian Fish-fauna of Spitz- 

 bergen. Ann. tto Mag. Nat. Hist., ser. 6, vol. viii. 



Workman, I. S. 1900. The Ophthalmic and Eye Muscle-nerves 

 of the Catfish. Journ. of Comp. Neurol, vol. x. 



EXPLANATION OF THE PLATE. 



Fin;. 1. Dicti/onosteus arcticus Stensio. Anterior half of the iieurocranium in 



lateral view. The lateral parts of the ethmoidal region and of the cranial 



roof removed. 1/2. 

 Fig. 2. Diotyonosteus arcticus Stensio. Same parts as in the preceding figure, but 



with the basipterygoid process removed to show the canal for the pituitary 



vein and the fossa hypophyseos. 1/2. 

 Pig. 3. Dictyoiiosteus arcticics Stensio. Sphenoid from behind. 1'2. 

 Fig. 4. Diotyonosteus arctictis Stensio. Autero-lateral view of the posterior half 



of the sphenoid. N.B. The very distinct sulcus for the jugular vein (.s/), 



and the opening of the canal for the pituitary vein {v.pit). 1/2. 

 Fig. 5. Porolepis ?sp. Anterior part of tire dermal cranial roof, showing the 



sensory canals. 



The type-specimen of figs. 1-4 belongs to the Palseontological Institution, Upsala 

 the type-specimen of fig. 5 to the Palajontological Museum, Christiania. 



Index letters. 



IS.pethm, exethmoideo-preethmoid ; J?r, frontal; PspA, . parasijlienoid ; Sph, 

 sphenoid ; c.car.int, canal for the arteria carotis interna ; alspli, alisphenoid 

 wulst; by, basipterj'goid process; en, orbito-nasal canal for vessels to or from, or 

 both to and from the nasal pit ; c.ofhth.lat, through the dorsal part of tlie 

 alisphenoid wulst for the u. ophthalmicus lateralis ; cv, cranial cavity ; f-hyp, 

 fossa hypophyseos ; ifc, infraorbital sensory canal ; sj, sulcus for the vena jugularis ; 

 soc, supraorbital sensorj' canal ; v cerebr.ant, canal for the anterior cerebral vein ; 

 v.pit, canal for the pituitary vein; I, olfactory canal; II, opticus canal; III, 

 oculomotorius canal ; IV, trochlearis canal; V, trigeminus exit ; Vi, canal for the 

 r. ophthalmicus profundus. 



