;Uf) PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxv. 



MiUixinrments. — Length (approximate), 18.2 mm.; width (ap- 

 proximate), 27.2 mm. ; height at least 5 mm. 



Relationship. — There is no recent form closely approximating the 

 above. The characters of the carapace point more strongly to the 

 Parthenopidse than to any other family, but it is possible that a 

 knowledge of the appendages would compel the removal of the genus 

 to another family. The general shape as well as the antero-lateral 

 teeth and the orbits are Parthenopid. The front is more Cancrid. 

 The suberect postero-lateral surfaces may be analogous to those in 

 Solenolambrus. The amplitude of the branchial regions and the cor- 

 responding contraction of the cardiac and gastric regions are unique. 



List of fossils from Vaqueros formation (lower Miocene), immediately over- 

 lying beds containing Branchiolambru.s altus at Wagon Wheel Mountain, Kern 

 Count)/, 86 miles southeast of Goalinga, California. 



ECHINOIDEA. 



Astrodapsis merriami Anderson. 



PEI.ECYPODA. 



Ghione temblorensis Anderson. Pecten andersoni Arnold. 



Metis, species. Pecten arassicardo Conrad. 



OASTKROPODA. 



('onus, species. Siphonalia (?), species. 



Turrit ell a oeoijana Conrad. 



Family OCYPODI1XF. 



Genus ARCH^EOPUS, new. 



Carapace transverse, sides converging anteriorly, posterior angles 

 rounded. Front or rostrum linear; orbits deep and wide. Basal 

 joint of antennules very large, inflated, and much exposed. Buccal 

 cavity wide. Chelipeds of moderate size; fingers long and slender. 

 Last pair of legs very small, subdorsal and probably attached at the 

 margins of the abdomen which does not cover the whole width of 

 the sternum at its base. 



(apxaios, belonging to former times; tto-i-s-, foot, in allusion to the 

 reduction of the last pair.) 



Type <>f the genus. — Arehmopus antennatus, new species. 



Allied to Plagiolophus Bell." in which, however, tin 1 four ambula- 

 tory legs are similar to one another, and the orbits are less extensive. 

 The carapace of our species has a strong resemblance to that of the 

 so-called Plagiolophus Vancouver ensis Woodward, 6 but in that species, 

 although the orbits extend to the anterior corners of the carapace, 

 the front or rostrum is of considerable width and bifid, and. as 

 mentioned above, the hind feet are not known. 



" Mon. Fossil Malac Crust. Croat Britain, Pt. 1. 1857, p. 10. 



6 Quart. Jour. Geol. Soc. Loudon, Id I. L896, p. L'^'U. text li^s. 5, 6. 



