26 J. Hopkinson — On a New Genus of Oraptolites. 



Loc. Llandeilo ;— Dobb's Linn, Hartfell, and Glenkiln Burn, near Moffat, Dum- 

 friesshire.i Caradoc /—Albany, New York (Hudson River Group). 



5. Dicellograpsus anceps, Nich., sp. Didymograpsus anceps, Nicli. 

 (1867), Geol. Mag., Vol. IV., p. 110, PL VIII., Fig. 18-20.— PI. I., 

 Fig. 5. 



Branches of polypary nearly straight, diverging from each other 

 at a very small angle, and with or vv^ithout an axillary spine. 

 Hydrothecse from 25 to 30 to the inch ; as long as the width of the 

 polypary, and free for about half its width. Eadicle and lateral 

 spines not known. 



The branches are " very little narrower at their origin than elsewhere," and retain 

 a nearly uniform width of about l-20th of an inch, varying slightly in different 

 individuals. They diverge from each other at an angle of from 6 to 10 degrees. 

 The axillary spine, when present, varies in length " from a mere node up to nearly 

 one line." In the few specimens as yet obtained, no radicle or lateral spines have 

 been detected. The hydrothecfe differ but little from those of the other species of this 

 genus. They are described as having "their outer margins curved and nearly parallel 

 to the axis ;" they are rounded off distally, and their apertures open towards oblique 

 pouch-like indentations, as in the other species of Dicellograpsus. In some specimens 

 the first few hydrothecas "are provided each with a short blunt spine proceeding from 

 the centre of their outer margins ; " and sometimes there are minute pustules in 

 the centre of each hydrotheca. 



Not having seen this species, I have drawn up the above description from that given 

 by Dr. Nicholson in his paper on "Didymograpsus.'" For its specific distinctness, 

 the small angle of divergence of the branches, the presence of an axillary spine, and 

 the absence of proximal spines, are the chief points relied on. 



Loc. Llandeilo :-~\ioWs Linn, Moffat, Dumfriesshire. 



Perhaps I may here be permitted to express my obligations to Mr. Carruthers, who 

 very kindly allowed me to select from his extensive collection of Graptolites most of 

 the specimens from which the figures in the accompanying plate have been drawn ; 

 and to Mr. Etheridge, for enabling me to examine the collection in the Museum of 

 Practical Geology. 



EXPLANATION OF PLATE I. 



Fig. 1. Dicellograpsus Forchhammeri, Gein., sp. la. A specimen natural size. \b. 

 A portion of the same magnified 5 diameters. \c. The proximal end of 

 the same mag. 10 dia. \d. Part of a branch of another specimen, slightly 

 restored, mag. 5 dia. (for comparison with Geinitz' fig. 28«). 



Fig. 2. Dicellograpsus Morrisii, Hopk. 2a. A specimen nat. size. 2b. A portion 

 of the same mag. 5 dia. 2c. A specimen much bent and showing pro- 

 longed solid axis, nat. size. 2d. Part of the same mag. 5 dia. 2e. A 

 young specimen nat. size. 2/. Part of the same mag. 5 dia. 2g. One 

 much younger, nat. size. 2h. The same mag. 5 dia. 



Fig. 3. Dicellograpsus elegans, Carr., sp. 3a. A specimen nat. size. 3b. Two 

 hydrothecse of the same mag. 10 dia. 3c. Another specimen nat. size. 

 3d. The proximal end of the same mag. 5 dia. 3e. The extremity of a 

 branch of the same mag. 5 dia. 



Fig. 4, Dicellograpstfs Moffatensis, Carr., sp. ia. A specimen nat. size. 45. Part 

 of the same mag. 5 dia. (The branches in this specimen diverge at a 

 smaller angle than usual). 



Fig. 5. Dicellograpsus anceps, Nich., sp. 5a. A specimen nat. size. bb. A portion 

 of a branch mag. 5 dia. (Restored from the drawings and descriptions 

 of Dr. Nicholson.) 



1 Dr. Bigsby, in his " Thesaurus Siluricus," (p. 82) gives " "West of Stiper Stones, 

 Shropshire," as a locality for this species, but this is most probably an error. 



