REPORT ON THE CRUSTACEA MACRURA. III! 



Pentacheles, Sponcc Bate. 

 Pentacheles, Sp. B., Ann. and Mag. Nat. Hist., ser. 5, vol. ii. p. 276, 1878. 



All the pereiopoda are more or less perfectly chelate in both sexes, the ophthalmo- 

 poda are immovably lodged in a notch in the anterior dorsal surface of the carapace, and 

 the anterior portion projects beneath the antero-lateral angle of the carapace, which 

 is produced anteriorly to a level with the central rostral tooth. 



Geographical Distribution. — The range of this genus comprises probably the whole 

 Pacific and Atlantic Oceans, as species have been taken in the sea around the Philippine 

 Islands as well as on the western coast of South America and at the intermediate 

 stations of the Fiji and Kermadec Islands. A. Milne-Edwards describes two, Pentacheles 

 validus and Pentacheles agassizii, from the West Indian region of the Atlantic, and 

 Sidney Smith has taken Pentacheles sculptus in Mid Atlantic. 



Pentacheles obscura, Spence Bate (PI. XV. fig. 2). 



Pentacheles obscura, Sp. B., Ann. and Mag. Nat. Hist., ser. 5, vol. ii. p. 279, 1878. 



Carapace furry on the dorsal surface. Lateral margins furnished with few teeth, 

 not conspicuous from being intermingled with hairs. Regions not well defined mar- 

 ginally. Anterior division furnished with three or four small teeth separated from each 

 other, median with three, posterior division with five or six. Anterior median armed 

 with two rostral teeth ; half way to the cervical suture are two more, posterior 

 to which is one small one, and the rest of the median ridge is either smooth or crested 

 with small granulations. Pleon carinate ; central ridge tuberculate rather than 

 denticulate. 



Length, 25 mm. (1 in.). 



Habitat. — Station 218, March 1, 1875 ; lat. 2° 33' S., long. 144° 4' E., north of 

 New Guinea; depth, 1070 fathoms; bottom, blue mud; bottom temperature, 36°'4. 



This specimen is in a very poor condition, and has much the appearance of one 

 that had recently cast its skin. The dorsal surface of the carapace is of a rougher 

 character than usual, the small granulations that carry the short curved hairs being 

 rather prominent. The median ridge is furnished with a double row of granulations, 

 except at the anterior excremity where there are two small teeth side by side, and 

 there are two others similarly placed on the gastric region. The denticulation of the 

 lateral margin is not clearly determinable in consequence of its hirsute character. 



The ophthalmopoda support a strong tooth, rather longer than usual, and are 

 implanted in a wide-mouthed but not deep notch. 



The first pah- of antennas has the inner margin of the first joint of the peduncle 



