specimens were really distinct, and again two genera Hylaeocarcinus and Limyiocarcimis. were 

 established. The inner suborbital lobe in some specimens unites with the front, in others, 

 however, a wide space is left, and this variability caused the authors above named to regard 

 their specimens as belonging to a genus different from Gecarcoidea. The inner suborbital lobe 

 is separated by a more or less wide fissure from the infra-orbital border. 



The genus is most closely related to Gecarcintis. with which it agrees in all principal 

 points: in the width of the front and of the orbits together being not quite half the greatest 

 width of the carapace, in the curvature of the lateral margins of the latter, in the course of 

 the grooves on the carapace and in the shape of chelipeds and walking legs. The external 

 ma.xillipeds, too, are largely equal, but the merus is much shorter and narrower than the 

 ischium, and the very short flagellum is with its carpus partly concealed behind the merus. 



Ortm.anx already pointed out, that there is only one single species, to which four 

 generic and five specific names have been applied. 



I. Gecarcoidea lalandei H. Milne-Edwards. 



Literature: Ortmann, Zool. Jahrb., Syst., Bd 7, 1894, p. 738; Calman, Proc. Zool. Soc. 

 London, 1909, p. 710. 



Stat. 133. Lining, Talaut Islands. 6 cT- 



The specimens before me fully illustrate the variability presented by this species in the 

 contact of the inner suborbital lobe with the front and in the width of the suborbital fissure. 

 According to Wood-Mason [Hylaeocarcinus Iiumei) ') the mesogastric lobe is studded with 

 granules, but probably this character disappears with advancing age; at least they are absent 

 in mv adult specimens and de Man ■) states the same in his Limnocarcinus intermedius. From 

 either side of the hairy epistome a crenulated and concave crest runs laterally beneath the 

 orbit; near the epistome it is rather high, but this height soon decreases laterally; its total 

 length is about three times the transverse diameter of the orbit. 



With reference to our still limited knowledge of the Gecarcinidae it is worth to note, 

 that Andrews ^) observed at Christmas Island the migration of numbers of the present species 

 towards the sea, to propagate. This occurred during the rainy season, and in 1908, shortly 

 after the migration, he obtained enormous quantities of Megalopa-larvae and of small crabs 

 near the shore, which, according to Calman, are most likely the young of this species. 



Besides at the locality named the species has been observed at the Nicobars, Andamans 

 Gorontalo (Celebes), Philippines, Loyalty Island, New Guinea and New Britannia. In the Leiden 

 Museum there is still a small specimen from Pulu Weh, collected by Dr. Buitendijk. 



The original locality (Brazil) of H. Miln^-Edwards is scarcely trustworthy. 



1) Journ. As. Soc. Bengal, v. 42, prt 2, 1873, P- 260, pi. 14 — 15. 



2) Notes Leiden Museum, v. 2, 1880, p. 65. 



3) Monograph of Christmas Island. 1900. p. 163. The author records this species erroneously under the name C<'<-(7/-ri«/« //7»».f/«»7/«o-. 



138 



