323 KEPOKT— 1873. 



graph on the Meeostomata have been printed, and form part of the volumes 

 of the Palaeontographical Society's annual fasciculus for 1871 and 1872 

 respectively. 



Part III. completes the genus Pterygotus, and contains descriptions and 

 figures of: — 



Pterygottis raniceps. Upper Silurian, Lanark. 



taurimis. Ditto, Herefordshire. 



ludensis. Old Red Sandstone, Kington, HerefcrdsMre. 



Banksii. Upper Ludlow, Ludlow. 



stylops. Upper Silurian, Kington, Herefordshire. 



arcuatus. Lower Ludlow, Leintwardine. 



gigas. Downton Sandstone, Hereford. 



■ — — problematicus. Upper Ludlow, Ludlow. 

 Slimonia acuminata. Upper Silurian, Lesmahagow. 



Part lY. completes the suborder ETJETPTEEinA, and contains descriptions 

 and figures of the following genera and species : — 



Stylonurus Powriei. Old Red Sandstone, Forfar. 



megalops. Ditto, Ludlow. 



; Syniondsii. Ditto, Rowlestone, Herefordshire. 



ensiformis. Ditto, Forfar. 



scoticus. Ditto. 



Logani. Upper Silurian, Lanark. 



Eury-ptcrus Scouleri. Carboniferous Limestone, Kirkton, Bathgate. 



5 lanceolatus. Upper Silurian, Lanark. 



;! — ^ pygiiKBus. Upper Ludlow, Kington. 



a acuminatus. Ditto, Ludlow. 



linearis. Ditto. 



^ • abbreviatus. Downton Sandstone, Kington, 



,1 • hibernicus. Old Red Sandstone, Ireland. 



g- Brewsteri. Ditto, Arbroath. 



scorpioides. Upper Silurian, Lanark. 



punctatus. Ludlow Rock, near Ludlow. 



obesus. Upper Silurian, Lanarkshire. 



o". Brodiei. Ditto, Herefordshire. 



Y( Hemiaspis limuloides. Upper Ludlow, near Ludlow. 



„j. speratus. Lower Ludlow, ditto. 



,. horridus. Wenlock Limestone, Dudley. 



.; Salweyi. Upper Ludlow, Ludlow. 



-XJ 



o'jTwo doubtful species of Eurypterus, namely E. mammatus, from theCoal- 

 ineasures near Manchester, and E. ferox, Coal-measures, Coalbrookdale and 

 Staffordshire Coal-field, have been examined critically ; and with regard to 

 j^l ■onammatiis, I have also had the great advantage of the assistance and rare 

 P^laeobotanical knowledge of my colleague, Mr. "W. Carruthers, P.R.S. 



A careful examination of the original specimens of E. mammatus has 

 enabled me to show that four out of the six specimens known and referred 

 by the late Mr. Salter to the genus Euryptems are plant-i-emains, referable 

 to the genus Ulodendron or to fragments of a large Equisetaceous plant, 

 and that the two remaining parts appear to belong to Jordan and Von 

 Meyer's genus Arthropleura, a nondescript crustacean (or, more probably, a 

 gigantic arachnid), only known at present by a series of obscure frag- 

 mt^i^ts from Saarbruck, £rom Manchester, and from Camerton CoUiery, near 

 l^ristol. 



^.J^e ornamentation as weU as the form of these pieces are totally unlike 

 any known Euryjjterus. 



Of Eurypterus ferox I am now able to state that it is not a Eurypterid, 

 ttutf-^s referable to Messrs. Meek and Worthen's American genus Euplioheria, 

 audithat it is a gigantic Mybiopod, much larger than our largest tropical 



