Lapworth— Graptolites of Co. Down. 
129 
14. Sp. 9. Monogrciptus lobiferus. M‘Coy. PI. 5, fig. 6. 
This species occurs in the black shales of Coalpit Bay in a few o^" the com* 
mon varieties, in all of which the extremity of each theca seems to form a 
rounded lobe, the aperture being apparently directed partly inward and partly 
upward against the lower wall of the central portion of the tube. According 
to Dr. Linnarsson, who has found specimens of this species in the lobiferus 
schists of Sweden, preserved in relief, the hydrotheca is actually coiled obliquely, 
and thus the aperture opens outward in a different plane to that of the 
proximal portion of the theca, which is wholly free. Locality— Coalpit Bay. 
In the grey schists of Tieveshilly this species appears to be represented by 
the following form : — 
is- Var. pandus. Lapw. Var. nov. PI. 6, fig. 3. 
Polypary simple, monoprionidian, stout, straight ; from four to six inches 
in length, and with an average diameter of % of an inch in the fully 
developed portion, inclusive of the projection of the hydrothecse. 
These are arranged in the proportion of from 24 to 28 to the inch, and 
are in contact only. They are broad at their origin, and have the 
superior margin almost horizontal. They narrow rapidly towards 
their outer extremity, which is bent downwards in the direction of 
the proximal extremity of the polypary. 
This form has been frequently noticed by palaeontologists, but its distinct- 
ness has not hitherto been acknowledged. Barrande (Grapt. de Boheme. PI. 1, 
figs. 10 to 14) and Geinitz (Die Graptolithen, Taf. Ill, figs. 24, 25, &c.) both 
refer it to Monogrciptus priodon. (Bronn). From that species, however, it is 
easily distinguished by the general form of the theca, and the absence of 
overlap. From Monogrciptus Clingani (Carr.) it differs in the size and shape of 
the polypary. Locality — Tieveshilly. 
16. Sp. 10. Monogrciptus priodon . Bronn. PI. 5, figs. 24a, and 24b. 
Locality — Tieveshilly. 
17 . Sp. 11 . Monogiaptus Riccartonensis. Lapw. PI. 5, fig. 23. Locality— 
Tieveshilly. 
18. Sp. 12. Monograptus Galaensis . ‘Lapw. PI, 6, fig. 1. Locality — 
Tieveshilly. 
