288 Ortmann — Crangopsis vermiformis. 



recognizable, and therefore its position among the Mysidacea 

 is not beyond doubt. Indeed, I do not believe that Crangopsis 

 really belongs to the order Mysidacea, but that it is related to 

 the Syncarida. At present, however, we are at a loss to ascer- 

 tain its true position, since the morphology of the appendages 

 of the body is unknown : yet there is much probability that 

 Crangopsis may be a transitional form from the true Syn- 

 carida to one of the more specialized groups of Thoracostraca, 

 namely the Mysidacea. Whether we shall connect it system- 

 atically with the latter group or with the Syncarida, depends 

 on the knowledge of the other details of structure. In the 

 latter case, the synopsis of the Syncarida ought to be changed 

 as to include this form provided with a carapace. 



I may be permitted here to direct attention to a few other 

 Malacostracous Crustaceans found in Palaeozoic strata, the 

 position of which with Crangopsis is likely more correct than 

 with the Decapoda. 



The oldest form referred to the Decapoda, Palceopalcemon 

 newberryi^ from the Upper Devonian of Ohio, has been 

 placed by J. Hall among the " Carididce /" but certainly it 

 does not belong to the typical forms of this group, as the name 

 might suggest, which are now called Eueyphidea. Zittelf 

 places this genus among the Penceidce. Although there is no 

 character known which contradicts this position, there is, on 

 the other hand, none which seems to warrant it. On the con- 

 trary, no characters are present at all which stamp this fossil as 

 a Decapod : it may belong equally well among the Euphau- 

 siacea or Mysidacea. Indeed, in the figure of the only known 

 specimen the carapace appears posteriorly elevated over the 

 abdomen as if separated from the trunk, a feature which sug- 

 gests a condition similar to that of the Mysidacea or Euphau- 

 siacea. But, of course, we cannot judge from this character, 

 as it might be due as well to fossilization. 



In the Coal Measures of England a peculiar Crustacean has 

 been found, described by Huxley under the name Pygoceph- 

 alus cooperi.% Huxley considers this form to come near to 

 the recent My sis, but to possess some relations to the Stomato- 

 pods, while Zittel places it among the Decapod-group Penmdce. 

 I should like to endorse the opinion of Huxley in so far as the 

 wanting chelae, the non-differentiation of maxillipeds and perei- 

 opods, and the presence of exopodites are strongly against its 



* Whitfield, this Journal (3), vol. xix, 1880, p. 41, and Ann. N. Y. Acad. Sei., 

 vol. v, 1891, p. 571, pi. 12, figs. 19-21. Hall, Pal. N. Y., vol. vii, 1888, p. 203, 

 pi. 30, figs. 20-23. 



f Handbuch d. Palaeont., ii, 1885, p. 683. 



% Quart. Journ. Geol. Soc, London, xiii, 1857, p. 363, pi. 13 and 18, 1862, 

 p. 420. 



