648 NEW YORK STATE MUSEUM 



Description. Primaiy disk aud uema not observed. Sicula iucon- 

 spicuous, about 2 mm long. Branches of first order (consisting of one tbeca) 

 narrow (.5 mm), 3.1mm long. Four branches of second order or main 

 stipes disposed horizontally, having a normal length of 30 cm, but attaining 



a maximal length of 60 mm and more ; those of either 



1 side forming angles ranging between 70° and 90°, 



^^jp^^^ widening within a few millimeters from the point of 



"^^^^^^^^W" bifurcation to the maximal Avidth (2 .9 to 3 mm), 



r^^Bbk^ which is maintained to near the distal end. Thecae 



Fijr. 53 Tetragraptus sUghtly curved, numbering 9 to 10 in 10 mm, 



amfi L.,E.&W. Younjir rhab- i , ., n • ^• ^ l i r\n • ii • 



(Idsome: one branch inissintf. ilDOUt 6 lUUl lomr, lUClineU at 40° HI tllCir averaije, 



Kevei'se view. Shows point of °' ~ ' 



;kJS''U-S""ximaf "poruourof of unifomi Avidth, three to four times as long as wide, 



liranches. Deep kill. x4. 



and overlapping about three fourths of. their 

 length. Outer walls concave, apertural margin concave, normal to the axis 

 of the theca. 



Positio7i and localities. Hall does not state the locality of the specimen 

 Avhich is referred by Elles and Wood to their new species. At the Deep 

 kill Ave have observed this form only in graptolite bed 2 (Tetragraptus 

 zone), where it is found associated with T. serra, T. fruticosus, 

 Phyllograi:)tus ilicifolius, Didymograptus extensus, 

 etc. The authors of the species record it from 

 the Middle SkiddaAv slates, in association with 

 some of the species just mentioned ; and from 



south Wales. pig 5^ Tetragraptus amii L., 



j~. , mi T ,TT T , ; • ,1 • E. & W. Fragment of branch. Deep 



Jxemarks. bJles antl Wood state m their wn. x3.3 

 work that this form was included by Hall (with 



doubt) in T. bryonoides ( = serra), and that Lapworth long con- 

 sidered it as distinct. Also, the present writer had recognized the differences 

 between this form and T. serra, when the description of the species was 

 published. While tlie dimensions and characters of the branches and thecae 

 are the same as in T . serra, the branches are here disposed horizontally, 

 instead of being reclined as in that form. This difference is most strikingly 



