^iJ 



ACADEMY OF SCIENCES. 



V 



AUrgatis cristatissimo. Lockington. Proc. Cal. Acad. Sci., March 20, 187G. 

 La Paz, San Jose Island, Amortiguado B&y. 



This jwetty little species does not appear to occur on the west coast of Low- 

 er California. 



The color of the carapax in spirits is the same as in the dried specimen, 

 viz., bright red. 



No. 30. Two males, dried. From La Paz. D. E. Hnngerford. 



No. 42. Male and female, in spirits. W. N. Lockington. 



A.ctcea meandncus. nov. s]). 



Front four-lobed, antero-lateral margin without conspicuous teeth; postero- 

 lateral margin highly concave. 



Entire upper surface of the carapax covered with involved ruga;; those of 

 each areolet distinct; areolets separated by sulci. 



Chehpeds equal, their upper outer surface rugose like the carapax, the 

 rugas giving way to rows of tubercles on the underside of the manus. 



Upper edge of the manus and carpus an acute angle; inner surface of both 

 perfectly smooth; meros smooth on both sides, compressed. 



Hinder limbs with compressed joints; the meros smooth on both sides, ex- 

 cept in the fifth pair; the remaining joints rugose on their upper and posterior 

 aspects. Meros of fifth pair rugose above. Fingers of chelipeds sulcate, 

 short. Sternum cavernous; abdomen with transverse rugte. Color, in spirits, 

 dull red. 



Locality, Mulege Bay, Gulf of California. 



Two specimens, a male and female, are all I have seen of this well marked 

 species. 



M. M. M. M 



Greatest length * 20 19 



Extreme width of carapax 27 25 



This little crab has a peculiarly compact appearance. The rugosities of its 

 limbs are so arranged that when they are folded up close to the carapax not a 

 portion of smooth surface can be seen either above or below, the only smooth 

 portions being lateral and hidden. 

 HeteractoM. nov. genus. ^^;^thmj^'iv F/'lu m ?l((^ 



Form of carapax as in AcUva, but with an external hiatus to the orbit, and 

 its lower margin divided into two lobes. Abdomen of male, five-jointed. 



I am loth to form a new genus for a sjjecies which resembles an Acla'a so 

 closely in its general aspect and form, which, in my belief, aflford far better 

 evidence of the real affinities of any animal than are afforded by variations in 

 the form of the orbit or the length of the basal joint of an antenna; but I 

 have no choice in the matter, as the genus Adwa is defined as "without an 

 external hiatus to the orbit," while the genera with the lower margin of the 

 orbit divided into teeth have a seven-jointed abdomen in the male. 



Heteracto'a pih3u»r ji©T7T5p. //^eii. TiZlZ US Cuiri^i US \ BUx^ih iLu^': ^3 



Aspect that of an AcUia, but the orbit with an external hiatus, and its 

 lower margin divided into two separate lobes. Front two-lobed, upper mar- 



