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2. Branchial and anterior cardiac region with a continuous, transverse 



ridge across the carapace. Epigastric lobes distinct, sharp . . P . cristatum de Alan l ] 

 Carapace smooth, without transverse ridge. Epigastric lobes indistinct, 

 not sharp 3 



3. Lateral margins of carapace with a prominent tooth, a little anterior 



to the middle of their course, anterior part concave, external 

 orbital angle produced. Walking legs long, meropodites of 2 d 



and 3 d pair very much elongate P. dentatum n. sp. 



Lateral margins of carapace regularly arched, not toothed. Walking 

 legs not elongate 4 



4. Anterior margin of front 0.3 of maximum breadth of carapace. 



5 th segment of abdomen of c? about as broad as long, with 



parallel lateral margins. Movable finger of cheliped curved . . P. leachii (Audouin) -) 

 • Anterior margin of front 0.2 of maximum breadth of carapace. 

 5 th segment of abdomen of c? fused with the preceding and 

 with convergent lateral margins. Movable finger of cheliped 

 straight, fingers widely gaping P. depressum de Man s ) 



1. Paracleistostoma dentatum n. sp. PI. 3, Fig. 2. 



Stat. 66. Saleyer Island, near south point of Celebes. Depth varying from 9— 34 M. 1 9- 



This small species is at once distinguished by the prominent tooth on the sides of the 

 carapace, and by the elongate shape of the meropodites óf the walking legs, especially in the 

 case of the third pair. 



The carapace is not so much flattened as in P . depressum (the only species with which 

 I could compare it), uneven in the middle parts and sloping towards the sides, especially on 

 the outer parts of the branchial regions; in longitudinal direction it is rather much vaulted. 

 The various regions are not very distinct, and the whole surface is hairless, with scattered 

 punctae (only visible by a rather strong magnification), except on the gastric and cardiac area. 

 The cervical groove, which is found anterior to a line connecting the lateral teeth of the 

 carapace and so lying nearer to the supra-orbital border than to the posterior margin of the 

 carapace, is short, concave forward ; the gastric region is faintly or not at all defined laterally, 

 but, so far as can be observed, much narrower than the very broad cardiac region. At the 

 base of the front the two epigastric lobes are visible as sharp, transverse ridges, scarcely 

 separated one from another, and immediately behind the lateral part of each there is a small 

 and shallow depression on the epigastric region. The cardiac area is much broader than the 

 gastric region, owing to its lateral parts being auriculate in their posterior half; its length in 



1) Ckhtostoma dilatatum Ortmann nee de Haan. Zool. Jahrb., Syst., Bd 7, 1894, p. 733. Hab. Japan. De Man (Zool. Jahrb., 

 Syst., Bd 8, 1895, P- 59°) afterwards studied the very specimens of Ortmann. 



2) For literature on this Red Sea species see Nobili : Ann. Sc. Nat. (9) t. 4, 1906, p. 316, for description : DE Man, Milt. 

 naturhist. Mus. Hamburg, n° 13, 1896, p. 90. 



3) De Man, Zool. Jahrb., Syst., Bd 8, 1895, p. 581, pi. 14, f. 13. Hab. Tenang and Pontianak. 



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