RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. 159 



XI. — DIAGNOSES OF NEW SPECIES OF MACRUROUS DECAPOD 

 CRUSTACEA FROM THE SIBOGA-EXPEDÏTION. 

 BY Dr. J. G. DE MAN. 



Family Stylodactylidae. 



Stylodactylus A. M.-Edw. 



Stylodactylus Sibogae n. sp. 



Stat. 95. 5°43'.5 K, 119°40'E. Sulu Sea. 522 m. Stony bottom. 1 female. 



Distinguished from all the other species of the genus by the lower 

 margin of the rostrum being smooth and glabrous. Rostrum horizontally 

 projecting to about the middle of 2 nd joint of antennular peduncle, armed 

 above with 16 subequal teeth, of which the first six stand on the cara- 

 pace; these proximal teeth are separated by very short distances, but 

 the rest are contiguous; anterior tooth at one-fifth the length of the 

 rostrum from the acuminate tip. Carapace with small supraorbital, an- 

 tennal and branchiostegal spine. 



Abdomen 6-times as long as the rostrum, 4-times as long as the 

 carapace and a little more than twice as long as carapace and rostrum 

 taken together. The abdomen resembles that of Stylod. amarynthis de Man, 

 but the pleura are smooth, quite unarmed, devoid of spines. 



Eyestalks cylindrical, almost half as long as carapace, cornea semi- 

 globular, measuring two-thirds the length of the rest of the stalk, dis- 

 tinctly faceted, of a pale grayish colour, blackish near the posterior margin. 

 Antennular peduncle little shorter than carapace, very slender, 10 to 11- 

 times as long as thick, basal joint more than twice as long as the two 

 following combined, 2 nd one and a half as long as 3 rd . Antennal scale 

 reaching by one-fourth its length beyond the antennular peduncle, narrow, 

 the greatest width, proximally, being one-sixth the length ; outer margin 

 concave, terminal spine reaching beyond the truncate tip of the lamellar 

 portion. 



Second and third maxillipeds, like also the peraeopods of the 1 st and 

 2 nd pair, resembling those of Stylod. amarynthis, but not armed with 

 small spines. The three posterior legs are of a more slender shape than 

 those of Stylod. amarynthis, so e.g. are the merus of 3 rd pair 11 -times, 

 the carpus 4-times and the propodus 11-times as long as broad; dactylus 



13 

 (3— IX- 191b) 



