660 J. HOPKINSON AND C. LAPWOETH ON THE GEAPTOLITES OF 



1865. Retiolites ensiformis,TLall, Grapt.Quebec Group, p. 114, pi. xiv. 

 figs. 1-5. 



About half an inch in length, attaining a maximum breadth of one 

 tenth of an inch about the centre of its length, the margins 

 converging towards both extremities, each of which is obtusely 

 pointed and wholly devoid of ornament; virgula central, straight; 

 hydrothecaB alternating, about 30 (?) to the inch. 



This brief description includes all the characters it is possible to 

 discover in the very badly preserved examples of this species which 

 occur in the shales of Ramsey Island. The hydrothecse are invisible 

 directly ; but their number and positions are deduced from the pre- 

 sence and place of some regular but almost invisible depressions in 

 the line of the otherwise perfectly plain lateral margins of the poly- 

 pary. What appears to be the virgula is visible as a straight but 

 very faint longitudinal stain running exactly down the centre of one 

 of the examples. The peculiar subfusiform shape of the polypary in 

 this species comes out clearly in a few specimens ; others are trun- 

 cate at their distal extremities, and may possibly be diminutive 

 examples of the species next to be described. 



Loc. Lower Arenig, Road Uchaf, Ramsey Island. 



Teigonogeapttjs tettncatus, Lapw., sp. nov. PI. XXXI Y. figs. 

 9a-9d. 



Half an inch to one inch in length, with an obtusely rounded proxi- 

 mal extremity, attaining a maximum width of one sixth of an 

 inch at its distal end, which is limited by a perfectly straight 

 line; ventral margins plain, slightly curved; virgula undu- 

 lating (?) ; hydrothecaB 30 or more to the inch ; epiderm very 

 thin, but apparently continuous. 



We name this species with some doubt, as the surface characters 

 of the polypary are so very obscure. The feature chiefly relied upon 

 in support of its specific distinctness is the very peculiar form of the 

 polypary. Several examples have been obtained, and the general 

 shape and proportions are very similar in all. The proximal extre- 

 mity is broadly rounded ; and there is a continual increase in diameter 

 throughout, the maximum width being attained at the distal extre- 

 mity, where the polypary is abruptly terminated in a perfectly 

 straight line. There is, however, a greater proportional expansion 

 about the middle of the polypary ; and the ventral margins are con- 

 sequently a little curved. The undulation of the virgula is a doubtful 

 feature ; neither is it possible to be certain of the number and incli- 

 nation of the thecae. 



The great breadth and straight distal end of the polypary in this 

 form clearly separate it from the foregoing species. It approximates 

 closely, in some respects, to Trigonograjptus lanceolatus of Nicholson ; 

 but its form and size are very different. 



Loc. Lower Arenig, Road Uchaf, Ramsey Island. 



