120 



In the H. gammaroides M'' Coy the carapace is comparatively 

 narrower both at the front and at the back, and it seems to 

 have a deeper incision at the back in the middle line than in 

 the Greenland species. The two keels which start from the 

 rostrum do not reach so far back on the carapace in H. 

 gammmaroides M° Coy; moreover the cervical furrow in this 

 species is considerably nearer the middle of the carapace, and the 

 spine under the postorbital ridge is situated somewhat farther 

 forward. Also the construction of the chela seems to be some- 

 what different, especially with regard to the right one. On 

 account of all these little differences I consider it advisable to 

 regard the Greenland specimens as belonging to an independent 

 species, remarking however that, although rather improbable, 

 I do not think it quite impossible, that by further comparison 

 it may prove to be identical with H. gammaroides ]VP Coy. 



H. groenlandica n. sp. differs so much from Hoploparia 

 Klebsii NoETLiNG^) that any confusion of the two species may 

 be considered impossible. 



The Coeloma-bed: 4 specimens. 



19. Coeloma bicarinatum n. sp. 



Plate IV, fig. 6; plate V, figs. 1 — 6. 



The carapace is trapezoidal, its length is about Vs of its 

 breadth; in a specimen in a very good state of preservation the 

 measurements are relatively 22 mm. and 28 mm. (The following 

 measurements of the carapace also refer to this specimen.) The 

 greatest breadth is formed by a line between the two spines 

 farthest back on the anterio-laleral margins; about ^li of 

 the length of the carapace lies in front of this line, and 

 about */7 of the length behind it. The upper side is rather 



^) F. Noetling: Die Fauna des samländischen Tertiärs. I. Th. — Abhandl. 

 zur geol. Specialkarte von Preussen und den Thüringsch. Staaten. Bd. 6, 

 Heft 3. Berlin 1885. p. 436; pl. 7, figs. 1—4; pl. 8; pl. 9, fig. 1. 



