Stylonurus (Ctenopterus) excelsior Hall
Stylonurus excelsior (Stylomurus in error) Hall (Martin). N. Y. Acad. Sci. Trans. 1882. 2: 2
Stylonurus excelsior Hall. N. Y. State Mus. 36th An. Rep't. 1883. p. 77, pl. 5, fig. 1
Dolichocephala lacoana Claypole. American Philosophical Soc. Proc. 1883. 21: 236, pl. 3
Stylonurus excelsior Hall. American Assn. Adv. Sci. Proc. 1884. 33: 421
Stylonurus excelsior Hall & Clarke. Palaeontology of New York. 1888. 7: 158, 221, pl. 26, 26A
Stylonurus lacoanus Beecher. American Jour. Sci. 1900. 10: 145, pl. 1
Only two specimens of this species are yet known. One a natural external mould of the complete carapace from the Catskill beds at Andes, Delaware co., N. Y., is in the possession of Rutgers College and is the type of Hall's original description. Another fragmentary carapace from the same formation in Pennsylvania, the original of Claypole's description, is now in the National Museum. Clarke succeeded in developing on the underside of the latter, a chelicera, one of the first pair of legs and the coxae of two legs of the succeeding pairs.
Both these specimens and the discovered appendages have been fully described by Hall and Clarke in Palaeontology of New York, volume 7, pages 158, 221, to which the reader is here referred for the details.
Professor Beecher subsequently selected S. excelsior for restoration on account of its gigantic dimensions, supplying the missing parts from the British species S. logani and S. powriei, and the American S. beecheri. The discovery by the authors of a specimen of S. cestrotus at Otisville retaining all save the first pair of legs, and the fact that S. excelsior is, according to the form and character of its carapace, manifestly more nearly related to that species than to any other, have suggested to us some corrections in this careful restoration which have already been dealt with in the preceding generic discussion. The
