Dr. H. Woodward — The Position of the MerostoTiiata. 293 



III. — The Position of the Mekostomata. 

 By Henry Woodward, LL.D., F.E.S., F.G.S. 



MOKE than fifty years since a great impulse was given to the 

 study of a new and strange group of Palaeozoic Arthropoda 

 whose remains were almost simultaneously brought to light in New 

 Tork, in England, Scotland, and in the Baltic island of Oesel, and 

 attracted the attention of numerous palaeontologists both in this 

 country and in America. Among others may be cited Hugh Miller and 

 the elder Agassiz, who at first believed them to be fish (1844), but 

 the latter afterwards was convinced that they were in reality the 

 remains of an enormous Crustacean. 



Professor M'Coy gave a weird restoration of Pterygotus prohlematicus 

 \nt\iebth.Qdiitionoi'Lje\V& Mammlof Elementary Geoloyy (1855,]). 4:20). 



Further discoveries of Pterygotus made by Mr. Robert Slimon, 

 on the banks and bed of Logan Water, Lanarkshire (1855), were 

 examined by Professor Huxley and Mr. J. W. Salter, and led to 

 the production of a Geological Survey memoir in 1859, illustrated by 

 sixteen folio plates and many text-figures. 



Mr. J. W. Salter contributed a restoration of Pterygotus anglicus 

 to Murchison's Sihiria (1859 edition), in which, although happier 

 than M 'Coy's figure already referred to, he gives only two pairs of 

 appendages to the head ; the thoracic plate, or operculum, is placed 

 in front of the mouth, and the lower lip or metastoma is absent. 



In the same year a Russian naturalist, Dr. J. Nieszkowski, 

 published an account of Eurypterus retnipes from the Upper Silurian 

 in the Island of Oesel, Baltic, giving restorations of the upper and 

 under sides of Eurypterus, showing the appendages of the mouth 

 in situ and the thoracic plates on the under side of the body 

 immediately behind the mouth. 



Following after Salter, Mr. David Page, in his Advanced Text-Book 

 of Geology (1859), gives restorations of several forms of Pterygotus, 

 Stylonurus, Eurypterus, etc., all more or less correct, but without 

 descriptions. 



Professor James Hall, the vetei'an geologist of the Albany Museum, 

 was the author of a most valuable monograph (1859-60) giving 

 excellent descriptions and figures of the American species of 

 Eurypterus and Pterygotus (see his Palceontology of New York, vol. iii, 

 pt. i, pp. 382-419*'', 80 plates and 10 additional plates), the accuracy 

 of which still remains unchallenged.^ 



In 1862 and 1863 Mr. J. "W. Salter contributed descriptions of 

 Eurypterus and allied forms of Pterygotus (Quart. Journ. Geol. Soc). 



The writer figured and described a very complete example of 

 Slimonia acuminata from the Upper Ludlow rocks of Lesmahagow, 

 Lanarkshire, in the Intellectual Observer, 1863 (vol. iv. No. iv, 

 pp. 229-37), and of Eurypterus lanceolatus (in the Geol. Mag. for 

 1864, Yol. I, p. 107, PI. V, Figs. 7-9). In 1865 he figured and 

 described Stylonurus scoticus, Stylonurus Powriei from the Old Red 

 of Forfarshire, and Stylonurus Symondsi from Herefordshire, also 



^ Thirty quarto volumes have been published by the New York State Museum, 

 fourteen of which, on Geology and Paleeontology, are by James Hall. 



