CRUSTACEA OF THE MEBGUI ARCHIPELAGO. 59 



These specimens agree very well with the description aud 

 figure given by Milne-Edwards, but I may add the following 

 details. 



In all the eight specimens the upper margin of the orbits is more 

 or less granular, and presents two fissures, so that this species 

 belongs to the subgenus Eupilumnus, established by Kossman 

 (Mr. Miers, I. c, erroneously mentioned the subgenus sensu stricto 

 Pilumnus). In all the under margin of the larger hand is covered 

 with rounded granules, except in the two largest males, in which 

 the granulation of the under surface of the larger hand gradually 

 begins to disappear. According to Dr. Hilgendorf (J. c), in the 

 true P. vespertilio the under surface of the larger hand is some- 

 what granular in the male but everywhere granular in the female, 

 so that there can be no doubt that these specimens are really 

 representatives of this species. 



Pilumnus ursulus, Ad. & White, and JPilumnus mus, Dana, are 

 identical with this species, according to Mr. Miers. 



Filumnus vespertilio is a very common species, distributed 

 throughout the whole Indo-Pacific region, having been observed 

 in the Eed Sea (Kossmann), at Mozambique (^Hilgendorf), Java 

 {Miers), Sydney {Hess), and on the coral-reefs of Australia 

 (Haswell), at New Caledonia, the Loo-Choo Islands, and Japan 

 {Stimpson). 



41. Pilumnus Ajs^dersoni, n. sp. (PI. III. figs. 5 & 6.) 

 Pour specimens ( 1 c? , 3 $ ) of this new species were collected 

 by Prof. Anderson in the Mergui Archipelago, two of which were 

 found at Elphinstone Island and two at King Island, One of the 

 female specimens is provided with eggs and another is infested in 

 its cephalothorax with a Sopi/rus. Courage, indeed, is necessary 

 to describe a new species of this genus, for the very numerous 

 species of Piluonnus, which, of ten closely resemble one another, 

 are rather insufiiciently known. I therefore sent a specimen to 

 Prof. Milne-Edwards, who informed me that this species was 

 unknown to him, although closely allied to Pilumnus Peronii, 

 M.-Edw., as I also supposed. As regards the species which 

 have been described by Stimpson, Hilgendorf, Miers, and Has- 

 well, I may remark that P. Andersoni is allied to P. Mrsutus, 

 Stimps., P. longicornis, Hilg., P. BleeJceri, Miers, P. terrce- 

 regincB, Hasw., and P. vestitus, '^a,sw., but is nevertheless a 

 distinct species in my opinion. 



