Report on the zoological collections made in the Indo-Pacific Ocean ...

?CRUSTACEA. 251The larger specimen closely resembles the specimens referred toM. affinis in the Museum collection, and scarcely differs from M. mammillarisexcept in the (relatively) somewhat longer, more acutemedian spine of the posterior margin, and shorter chelipedes ; and Ithink it probable that a larger series would demonstrate the necessityof uniting the two species. The younger examples may be distinguishedfrom those referred to iM. australis by their narrower carapace,and the longer, more acute, and non-recurved posterior marginalspines.100. Myra mammillaris, Bell.An adult male is in the collection from Port Denison, 4 fms.(?^o. 111).There are in the Museum collection specimens from Adelaide,S. Austraha (purchased), and others without special locality.101. Myra australis, i/asweZ/Mvra mammillaris (young), Miers, Trans. Linn. Soc. ser 2, Zool. i.p. 239, pi. xxxviii. tigs. 25-27 (1877).? Myra australis, Hasioell, Proc. Linn. Soc. N. S. W. iv. p. 50, pi. v.fig. 3 (1880); Catalixjve, p. 122 (1882).Three specimens are referred doubtfuUy to this form from PortMolle, 14 fms. (No. 93), and one from Port Denison, 4 fms. (No. 122)(first collection) ; also a male from Thursday Island, 3-4 fms.(No. 177), two females from the same locality, 4-5 fms, (No. 165),(to the back of one of which is attached a fine specimen of a speciesof Acetabularia), and two males from Prince of Wales Channel,obtained at 7 fms. (No. 142) and 9 fms. (No. 157).In some of the specimens I have examined the carapace is muchmore evenly granulated than in others, and they also differ in themore or less recurved posterior median spine and the greater orlesser dilatation of the intestinal region ; in some females the postabdomenis comparatively narrow, whereas in others it covers thewhole of the sternal surface. Although some of the larger specimensapproach nearly in their characters to 31. mammillaris, yet,as all may be distinguished by their more orbiculate carapace, moreacutely-angulated pterygostomian regions, the more or less recurvedposterior median spine, and relatively shorter chelipedes, I prefer toadopt for them, at least provisionally, Mr. Haswell's specific name.I should add, however, that in Mr. Haswell's figure the male postabdomenis represented as shorter than in our specimens, with thesides somewhat constricted at base of the terminal segment.There are specimens from Shark Pay, West Australia, in theMuseum collection (H.M.S. Hera " Id') which probably belong here,but in one (a female) the granulations of the carapace are veryindistinct.