of the Pacific Shores of North America. 471 



LEUCOSILIA JURINII. Bell. 



Guaia Jurinii, De Saussure ; Rev. et Mag. de Zool. 1853, v. 365, PI. XIII. f. 4. 

 Leucosilia Jurinii, Bell; Trans. Linn. Soc. xxi. 295, PI. XXXII. f. 1. 



Mazatlan, (Verreaux.) 

 Mus. Brit. 



EANDALLIA. nov. gen. 



Carapax ovalis, subglobosus, fere laevis, politus, dentibus duobus postice arma- 

 tus. Regiones pterygostomiani angulati. Prons angustata sed crassa, in 

 medio concava. Orbita trifissa. Fossae antennariae parvae, obliquae, altissi- 

 mae. Antennarum internarum articulus basalis operculiformis, fossam clau- 

 dens et partem super-mobilem retractam antennae celans. Epistoma ex com- 

 paratione ampla. Maxillipedes et pedes ut in Persephond. 



The species upon which this genus is founded was placed 

 in Ilia by Randall, and in Guaia [Persephond) by Gibbes. 

 Its characters will, however, exclude it from both of these 

 genera, although it approaches closely to the latter in its 

 general appearance. The following are its distinctive fea- 

 tures. The carapax is not depressed, and is armed with 

 but two teeth posteriorly ; the surface is mostly smooth and 

 ungranulated. Anterior extremity thick. Antennary fossae 

 small, oblique, and very deep. Basal article of internal 

 antennas somewhat expanded, operculiform, almost com- 

 pletely closing the aperture of the fossa when the antenna 

 is retracted within it. The fossae do not immediately border 

 on the buccal margin as in Persephona, but are separated 

 from it by a considerable space, so that the epistoma pre- 

 sents a greater surface than is usual in the family. 



EANDALLIA OENATA. Stimpson. 



Plate -XIX. f. 3. 



Ilia ornata, Randall ; Jour. Acad. Nat. Sci. Philad. viii. 129, 

 Guaia ornata, Gibbes ; Proc. Am. Assoc. 1850. p. 186. 

 Randallia ornata, Stimpson ; Proc. Bost. Soc. Nat. Hist. vi. 85. 



In this species there are generally a few granules on the 

 stomachal region anteriorly, and on the intestinal poste- 



