MQ THE VOYAGE OF H.M.S. CHALLENGER. 



Petrolisthes anmdipes (White), Miers. 



Porcellana annuUpeg, White, List. Crust. Brit. Mus., p. 6.3, 1847 {sine desrr.). 

 Petrolisthes an7iidipes, Isliers, Crust, in Zool. H.M.S. "Alert," pp. 270, .558, pi. xxix. fig. B, 

 1884. 



Habitat. — Station 186, Flinders Passage, North Australia ; depth, 8 fathoms ; bottom, 

 coral mud. Two females, one with ova. 



Miers has described this species from specimens collected by Dr. Coppinger in the 

 Australian Seas, and at He des Neufs, Indian Ocean. He suggests that it may prove 

 synonymous with Petrolisthes scabricula (Dana) from the Sooloo Sea, and Petrolisthes 

 militaris, Heller, from the Nicobars, but it is at least a very distinct variety. White's 

 specimen in the British Museum came from the Philippine Islands. 



Petrolisthes unilohatus, n. sp. (PI. XI. fig. 3). 



Characters. — The carapace is ovate and smooth, though minutely punctate, the 

 length considerably greater than the breadth, with a few faintly marked rugosities, 

 especially towards the branchial regions. The front is broad, and depressed towards the 

 apex which is obtuse, with a rounded excavation on each side for the ocular peduncle, while 

 in front of the latter the margin slightly dips down. The lateral border is convex and 

 entire, with a slight bulging in the anterior branchial region. The posterior border is 

 raised, with a double outline, and presents a broad posterior concavity. The cervical 

 grooves are well marked, uniting in front of the cardiac area to form a broad V-shaped 

 marking. The gastric area possesses two slight elevations situated opposite the posterior 

 border of the eye-stalks, separated by a shallow median groove which passes forwards 

 to the apex of the rostrum ; in front of these elevations the surface gradually slopes 

 downwards. The cardiac area is distinctly circumscribed. The branchial area is of con- 

 siderable extent and crossed transversely by a V-shaped impression, one limb of which 

 passes to the posterior part of the cervical groove, while the other reaches the outer 

 boundary of the cardiac area. The ocular peduncles are short and stout, with the 

 corneee deeply pigmented ; the antennal flagellum is almost twice the length of the 

 carapace. The pterygostomial area possesses a series of well-marked elevated lines. 



The ischium of the external maxillipedes has the inner margin broadly rounded, and 

 the outer and distal border prolonged into a subacute lobe, the external surface is crossed 

 by a few faint lines ; the merus has a large subacute lobe projecting from its inner 

 margin, and the external surface is traversed by a few oblique rugosities, especially 

 towards the outer border. 



The chelipedes are of moderate size and finely granular. The anterior border of the 



