216 DB, J. G. DB MAN ON" THE PODOPHTHALMOFS 



j8. Lateral margins of the carapace armed witlx an 

 epibranchial tooth. 



122. POBCELLAKA DENTATA, M.-Edw. 



Porcellana dentata, M.-Edwards, Hist. Nat. Crustaces, t. ii. p. 251. 

 Porcellana bellis. Heller, Crustaceen der Novara-Reise, p. JG, Taf. vi. 

 fig. 4. 



Petrolisthes Haswelli, Miers, Report Zoology Voyage of Jff.M.S. 

 ' Alert; 1884, p. 269, pi. xxix. fig. A. 



Fourteen specimens were collected, of which, eleven were 

 obtained at Owen Island and three at Sullivan Island. 



I was enabled by Dr. C. Koelbel, of Vienna, to study one of 

 Heller's types of P. iellis, and thus found out thab the Mergui 

 specimens were specifically identical with it. I then sent one of 

 the Mergui specimens to Prof. Milne-Edwards, who informed me 

 that it was identical with Porcellana dentata, M.-Edw. Porcellana 

 hellis, Heller, is thus a synonym of the latter. No doubt, more- 

 over, can be entertained that the Mergui specimens are also 

 representatives of P. Haswelli, Miers, from Australia. 



Porcellana dentata, M.-Edw., presents the following distinc- 

 tive characters : — the front is triangular, with the sides a little 

 emarginated, rounded anteriorly, and rather much prominent; 

 it is somewhat deflexed, and has a shallow, longitudinal, mesial 

 furrow. The gastric region is marked anteriorly, at the base of 

 the front, with two transverse linear elevations. The upper 

 surface of the carapace is punctate in the middle and posteriorly, 

 and marked with delicate transverse lines anteriorly and near 

 the sides ; these lines, when seen under a strong magnifying- 

 glass, appear to be provided anteriorly with microscopical haira. 

 Similar piliferous lines occur also in Porcellana Boscii, but in 

 it they are much more visible to the naked eye, and the small 

 hairs are also much longer. The lateral margins of the carapace 

 are cristate,. and terminate anteriorly in the acute epibranchial 

 tooth. The chelipedes are almost equal to one another. The 

 under margin of the meropodite is armed with a small acute tooth 

 about its middle, and the anterior margin terminates in a rounded 

 lobe at its external angle. The carpopodite measures nearly | of 

 the length of the carapace, and is nearly twice as long as broad. 

 Its anterior margin is armed with five or six teeth ; some of 

 them, however, are often obsolete, and in individuals not fully 

 grown only three or four teeth are found on this margin. The 



