312 Dr. R. V. Willenioos-Suhiu mt (lie 



and Labyrinthodonts of the Northumberland coal-field." Now 

 the illustration here referred to is not a restoration of the palate 

 of C. cn'stadis, Agassiz, but of that of ( '. tuhirculatits, nobis. 

 Secondly, he states that we describe the upper surface of the 

 tooth of C. cristatus as convex, whereas in reality we state 

 that it is " somewhat hollowed or concave." Our paper noticed 

 by Mr. Miall was published in the ' Nat. Hist. Trans, of North- 

 umberland and Durham,' vol. iii. p. 61, the illustration referred 

 to in vol. iv. pi. 14. 



EXPLANATION OF PLATE XL\'. 



Fiq. \. Outside view of right mandible of Ctenodus ohUquus, nat. size. 



Fig. 2. Right mandible, seen from above : a, articular piece ; d, dental 

 plate ; .s, symphysis of jaw. 



Fig. 8. Left pterygo-palatine bone, with dental plate attached, of Cteno- 

 dus vhliqimx, nat. size : a, anterior end ; pt, pterygoid border ; 

 p, palatine border; s, symphysis; sp, rough surface for articula- 

 tion with the sphenoid bone. 



Fig. 4. Vomerine tooth of CUnodus, nat. size : a, front, b, side, c, Ijack 

 view. 



XXXIX. — Notes on some Young Stages o/'Umbellularia, and 

 on its Geographical Distribution. By R. v. WlLLEMOES- 

 SuHM, Ph.D., Naturalist to the 'Challenger' Expedition. 



[Plate XVIII. A.] 



Since Umhellularia was rediscovered by the Swedish Expe- 

 dition to Greenland, the attention of zoologists has been 

 specially drawn to it by a paper, with excellent plates, by 

 T. Lindahl*, who himself brought it down from the Arctic 

 regions. Another note has been published by Prof. Kollikert 

 on specimens of Umhellularia which were brought up during 

 H.M.S. 'Challenger's' cruise in the Atlantic, and sent to him 

 for description by the hydrographer. Both authors were kind 

 enough to send us their papers ; and as in the mean time we 

 got a good many more Umhelhdnriop^ and even young stages 

 of them, I think a few notes on the geographical distribution 

 of the genus as far as it is now known to us will be welcome 

 to zoologists, as also will a few figui'cs of the earliest stages 

 which we brought up in the Antarctic Ocean. 



* "Om PennatulidslJigtet T'mhcllitla,'' Kongl. Svenska Akademiens 

 Handlingar, P.andet xiii.>.'o. 3, Febr. 10, 1h74. 



t ' Ueber den liau und die systemati.'Mjhe Stellungder Gattung Umhel- 

 lularia,' ^^'i^rzburg, 2. Mai, 1874. 



