S4 J, HopVinson — On a New Genus of GraptoUtes. 



In our only other description, that of Mr. Carruthers,^ the presence of the axillary 

 spine is recognized, and, for the first time, the species is stated to have three proximal 

 spines, the central one heing, as I have shown, the true radicle. Of the hydrothecse, 

 however, he merely says that they are " not very marked, in contact throughout their 

 whole length ; about 28 in an inch." 



Log. Llandeilo .•— Dobb's Linn and Hartfell, near Moffat, Dumfriesshire. Caradoc: 

 — Kilnacreagh, Co. Clare, Ireland.^ Bornholm, Baltic Sea. 



Dicellograpsus Morrisii, sp. nov. Didymograpsus flaccidus, Nich. 

 (1867), Geol. Mag., Vol. IV., p. 110, PL VIIL, Fig. 1-3. Bidymo- 

 grapsus elegans, Carr. (in part), Geol. Mag., Vol. V., PL V., Fig. 8& 

 and 8c (non Graptolithus flaccidus, Hall). — PL L, Fig. 2. 



Branches of polypary slightly curved, diverging from each other 

 at an angle of from 40 to 60 degrees, and with a short, obtuse, axil- 

 lary spine. Hydrothecse from 25 to 30 to the inch ; twice as long as 

 the width of the polypary, and free for about a third their length. 

 Eadicle and lateral s|)ines short and thick — rarely slender. 



The branches, frequently not l-60th of an inch broad at their origin, rapidly 

 widen, and maintain an average width of l-20th of an inch throughout their length. 

 At first widely divergent, they almost immediately attain their normal position, 

 making an angle with each other of about 40 degrees ; they then gradually widen, 

 increasing this angle, and again curve slightly inwards, making the same angle as 

 before. The persistent axillary spine varies from l-50th to l-30th of an inch in 

 length ; the radicle and its lateral spines usually corresponding with it, and with each 

 other, in form and size. The hydrothecae differ but little from those of B. Forch - 

 hammeri. They are a little more prominent, but scarcely so much elongated, and 

 more frequently appear as scalariform impressions. Opposite the depression in each 

 hydrotheca, in well-marked impressions, a row of minute pustules, or scars, may be 

 observed. 



From D. Forchhammeri this species differs in the general form of the polypary, 

 and the lesser divergence of its branches ; in its shorter axillary spine, and more 

 conspicuous radicle. 



From Hall's Graptolithus flaccidus, for which it has been mistaken by Dr. Nichol- 

 son, it is generically distinct. In this species the radicle is on the opposite side of 

 the polypary to the hydrothecse, the branches diverge at an angle of about 180 

 degrees, and the hydrothecse are of a very different form. From their similarity— in 

 the specimens I have examined, as well as in Hall's figure^ — to those of the genus 

 Nemagrapsus of Emmons {= Gladograpsiis, Carruthers), I believe G. flaccidus will 

 prove to belong to this genus, though it is not as yet known to have secondary 

 branches. From I), elegans, as the young form of which, Mr. Carruthers has figured 

 it, B. Morrisii may be distinguished by its possession of an axillary spine, and by 

 the form and dimensions of the polypary. 



I dedicate this species to ray valued friend. Professor Morris, who has always, from 

 his great store of scientific knowledge, most generously assisted me in my researches. 



Log. Llandeilo : — Beld Craig Burn, Dobb's Linn, and Hartfell, near Moffat, 

 Dumfriesshire. (In black anthracitic shale). Bilberry Rock, Waterford, Ireland (.'). 



3. Dicellograpsus elegans, Carr., sp. Didymograpsus elegans, Carr. 

 (1868), Geol. Mag., Vol. V., p. 129, PL V., Fig. 8a {non 8b and 8c). 

 —PL I., Fig. 3. 



Branches of polypary slightly curved and very slender, diverging 

 from each other at various angles, and slightly enlarged in the axil. 

 Hydrothecse about 25 (rarely fewer) to the inch ; two or three times 



1 Geol. Mag. Vol. V. p. 129. 



2 The specimen in the Geological Museum (Draw. vi. Tablet 19), labelled 

 " Bidymograjjsus sextans, Kilnacreagh," is a good example oi Bicellograpsus Forchham- 

 meri, showing the axillary spine, though indistinctly. 



3 Grapt. Quebec Group, pi. ii., fig. 19. 



