8 



Sv. Leonh. Tornquist. 



To this variety (or species) I have, long ago, referred a graptolite from Da- 

 larne, of which I possess one single, but distinct impression. It has a length of 

 15 mm., but seems to be broken off near the distal end. With the exception of 

 the proximal part, which is bent backward, the rhabdosome is straight, bearing 7 

 thecse in the space of 10 mm. These attain a length of from 1.4 mm. to 1.8 mm.; 

 when fully developed they are perceptibly reclined, and terminate in markedly 

 reflexed apices. In the curved region the internodes as well as the thecse are shorter. 



While this form agrees with the typical species in having reclined thecse, it 

 distinguishes from it by (1) longer internodes, (2) reflexed thecal apices, and (3) a 

 rectilinear mature division of the rhabdosome. 



Locality and horizon. Sweden: the example described is seen on a 

 detached slab found at En ån (Dalarne), and certainly derived from the zone of 

 Cephalograptus comela. 



Rastrites peregrinus Barrande, var. pecten v. u. 



Pl. 1, figs. 25, 26. 



The description of this variety has been drawn up from some fragments all 

 visible on the same slab. One of them representing the proximal part is recurved, 

 and bears eight thecse, all of which are directed outward and somewhat upward, 

 the eighth making with the internode next in advance an angle of 75°. The 

 thecse of this fragment augment in length from 1 mm. to 1.5 mm.; and the inter- 

 nodes, from .7 mm. to .8 mm. The fully developed rhabdosome is straight, but, 

 on account of the fragmentary condition of my specimens, its extent cannot be 

 made out even approximately. In this portion the thecae number 10 or 11 in 10 

 mm., and stand either normal to the stem, or deviate but little from this direction. 

 They have a length of from 2 mm. to 2.2 mm., and widen slowly towards their 

 rounded extremities, showing an average diameter of .2 or .3 mm. 



From the type species this variety is distinguished by (1) the straight distal 

 portion of the rhabdosome, (2) the upward direction of at least eight thecse in the 

 sicular region, (3) the right or nearly right angles formed by the mature thecas 

 with the common canal. 



Locality and horizon. Scotland: The specimens referred to were found 

 by me at Dobb's Linn in 1878. They were associated with specimens of Mono- 

 graptus fimbriatus Nich., whence their geological horizon can be appointed to the 

 zone of Monograptus gregarius. 



Rastrites peregrinus Barande, var. socialis n. v. 

 Pl. 1, figs. 27—31. 



Though numerous broken pieces of this graptolite are lying before me, none 

 of them exhibits the initial part, wherefore the general shape of the rhabdosome is 



