REPORT ON THE ANOMURA. 109 



specimens may show that Petrollsthes serratus is only a well-marked variety of the latter. 

 In Petrolistlies similis (of which typical specimens named by Stimpson exist in the 

 collection of the Paris Natural History Museum) the chelipedes have a shallow groove on 

 the upper surface of the carpus near its inner margin, the propodus is proportionately 

 longer, with its outer border and the whole upper surface less convex, and the granulations 

 are of larger size ; the transverse ridges on the gastric region of the carapace are more 

 strongly developed, and the frontal lobe is narrower, with a more pronounced median 

 concavity. 



Habitat. — Off Bahia, 7 to 20 fathoms. An adult male specimen. 



Genus Poixellana, Lamarck. 



Porcellana, Lamarck, Syst. des anim. sans vert., p. 153, 1801 {in part). 



„ Latreille, Gen. Crust, et Insect., t. i. p. 48, 1806 {in part). 



„ Desmarest, Consid. sur les Crust., p. 199, 1825 {in part). 



„ Milne-Edwards, Hist. Nat. des Crust., t. ii. p. 247, 1837 {in part). 



„ De Haan, Crust. Japon., p. 199, 1850 {in part). 



„ Dana, U.S. Explor. Exped., vol. xiii., Crust., part i. p. 410, 1852 {in part). 



„ Bell, Brit. Crust., p. 188, 1853 {in part). 



„ Stimpson, Proc. Acad. Nat. Sci. Philad., p. 66, 1858. 



„ Heller, Crust, siidlichen Europa, p. 181, 1863. 



„ Targioni Tozzetti, Crost. "Magenta," p. 210, 1877. 



„ Haswell, Catal. Austral. Crust., p. 147, 1883. 



Piddia, Leach, Diet. d. Soi. Nat., t. xviii. p. 53, 1820 {in part). 



Carapace suborbicular or subovate, the length usually greater than the breadth. 

 Frontal region prominent and dentate, the teeth usually well developed. Eyes of 

 moderate size, the orbits deep. Chelipedes moderately flattened, the carpus short and 

 usually provided with a single projecting lobe near the proximal end of the internal 

 margin ; the digits frequently contorted. Ambulatory limbs with the dactyli short and 

 robust, terminating in a single claw. 



Porcellana sayana (Leach). 



, Porcellana galathina, Say, Journ. Acad. Nat. Sci. Philad., vol. i. p. 56, 1817 (not Porcellana 



galatliina of Bosc). 

 Pisidia sayana, Leach, Diet. d. Sci. Nat., t. xviii. p. 54, 1820. 

 „ „ Desmarest, Consid. sur les Crust., p. 199, 1825. 



? Porcellana sayii, Gray, Zool. MisceU., p. 15, 1831. 



„ acellata, Gibbes, Proc. Amer. Assoc, p. 190, 1850. 



„ ,, Stimpson, Ann. Lye. Nat. Hist. New York, vol. vii. p. 77, 1859. 



„ sayana, Kingsley, Proc. Acad. Nat. Sci. Philad., p. 407, 1879. 



Habitat. — St. Thomas, West Indies ; shallow water. Several specimens, including 

 two females with ova. The colour markings have faded to a great extent, though 

 circular spots of light colour can still be recognised on the carapace and chelipedes. 



