56 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 37. 



pies this border in llelicoprion; and Karpinsky thinks that it might 



have conducted some kind of vessel. According to his view, the 



gutter was comj^leted below by a layer of shagreen, but I find no 



evidences of any such a covering. The sides of 



the shaft are unbroken and the edges bounding 



the gutter are smooth. 



The lateral surfaces of the shaft are covered 

 i)y a layer which looks as if it might be enamel. 

 For some distance below the teeth this is pitted 

 so as to resemble in miniature the pittings of the 

 carapace of a trionj^chid turtle; but low down 

 the enamel is raised into delicate ridges that 

 RiERi, XI. SECTION I'u^ i^arallcl with the shaft. Doctor Eastman 

 OF SHAFT AND TOOTH, has, lu defining Helicoprion, stated that the 



1, ENAMEL OF THIRD ., j.,i ic. i ii nil 



TOOTH; 2, GROOVE sidcs oi thc sliait are traversed b}^ a double 

 BETWEEN NARROWED lateral groove. This is, however, an error, which 



PROCESSES OF THIRD , ii.i • /• !• ^ i • j- 



AND SECOND TEETH; has (lOUDtless ariscu from a slight misconception 

 .-?, ENAMELED PROCESS of tlic scctlous pubHshcd bv Karpinsky." In 



OP SECOND TOOTH ; 4, , , „ , i , , i ' i • i 



EXPOSED PORTION OF ihosc figurcs tlic two iiotclies on each side repre- 

 shaft; 5, GROOVE sent, not sections of as manv longitudinal 



ALONG LOWER BORDER ' i;/> ' t / ^ l^ ^ i 



OF SHAFT. grooves, but or grooves between the downward 



])rolongations of the crowns of the teeth. There 

 are no longitudinal grooves in Lissoprion and no room for them on 

 the sides of the shaft of HeUcojmon. 



4. DESCRIPTION OF A NEW UENUS. 

 TOXOPRION, new genus. 



The type of this genus is Dean's Edestv.9 lecontei. Doctor Eastman 

 has recognized that this species did not belong to Fdestvs, inasmuch as 

 he included it in his genus Campylo prion; and afterwards, on remov- 

 ing the type of the genus, O. amiectens to Heliocoprion, he essayed to 

 make lecontei the type. The writer called attention to this matter in 

 ] 907.^ Even were this procedure admissible it w^ould not be advisable, 

 for the species annectens may yet prove to belong to a genus distinct 

 from Helicoprion and would then require the name C ampyloprion. 



The teeth of Toxoprion resembled most those of Lissoprion, but the 

 shaft, though strongly bent, formed only a part of one coil. In this 

 genus the present writer includes H. Woodward's Eclestus damsii, 

 found in Australia. In this species it will be observed that the wndth 

 is considerably reduced in passing from the newer to the older ends 

 of the specimen, so that it is not likely that a complete coil was 



" Verhandl. niss.-kais. niin. Oesellsch. St. Petersb., 2cl ser., vol. 26, 1898, p. 397, 

 figs. 30, 31. 



" Science, vol. 26, p. 22. 



