Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 57 



distinguishing charactfers from P. punctata; in orbicularis the front 

 is about the same width as in punctata, but the median depression is 

 shallower and the frontal margin is much less produced in the median 

 line. The pre- and postorbital angles are also much more heavily, 

 bluntly rounded than are those of punctata. This species is the "West 

 Coast analog of Persephona punctata Linne, In living specimens the 

 coloration of orbicularis is very different, being a blood red reticulated 

 with dull ocher on the central part of the carapace. P. orbicularis is 

 also densely covered with coarse pearly granules, whereas P. punctata 

 is covered with coarse punctae, and in rare cases, in old specimens has 

 pearly granules, but these are neither so large nor so abundant as in 

 orbicularis. 



Type: Mr. Bell's type was taken at Valaparaiso, Chile, by a Mr. Mil- 

 ler, a surgeon in the British Royal Navy, and deposited in the Bell 

 collection which is believed to be no longer extant. 



Distribution : Valparaiso, Chile, and Perlas Islands. Shallow 

 water. 



Material examined: One large male and one female taken at 

 Saboga Anchorage, Perlas Islands, March, 1928, by the "Ara," Wil- 

 liam K. Vanderbilt, commanding. 



Technical description: Carapace globose, very convex, densely 

 beaded with coarse, pearly granules; pterygostomian region promi- 

 nent, with a well-developed tooth pointing outward and forward. 

 There is evidently some variability in this spine. As shown in plate 

 11, it is most developed in the male, less so in the female. There is 

 prominent, outward and slightly upward directed tooth on the posterior 

 region in the median line but above the postlateral margin ; on either 

 side of this tooth outside and below it is a similar tooth, the three 

 forming a right angle. In the two West Coast specimens before me 

 the teeth are distinctly closer to each other than are those of P. punc- 

 tata, and the median spine is higher up on the carapace ; in fact, it is 

 the teeth are distinctly closer to each other than are those of P. punc- 

 tata. The side walls in orbicularis are very densely granulated, as is 

 also the sternal region and the abdominal belt of the female. The 

 female abdominal belt has the first, second and third segments narrow, 

 hinge-like, strongly vaulted in the median region, the fourth, fifth and 

 sixth segments are completely fused, forming a large, subcircular, con- 

 vex pouch which covers the entire sternal region between the chelipeds 

 and backward as far as the anterior margin of the fifth legs ; the sev- 



