34 



LOUD HOWE ISLAND. 



Island species, common on the reef. Other representative tropical forms are 

 PJiymodius ungulaius, M. Edw., and OMorodius nigcr, Porsk., the latter 

 being very abundant. By far the commonest Decapod at Lord Howe is 

 Ozius tnmoaUis, M. Edw., found everywhere on the rocks between tide 

 marks. It is of a remaikably active disposition, and possesses the faculty 

 of making its way into all sorts of crevices and corners. The largest we 

 obtained measured two and a half inches across the carapace, by one and 

 three-quarters. Another small species of Ozius, as yet unnamed, with the 

 fingers of the hand tipped with dark red, occasionally came under notice, 

 and is a very distinctly marked form. The Briphidse, besides the genus 

 Ozius, are represented by a species of Pilumnus, apparently not recorded as 

 Australian by Ilaswell, Actummis tomentosus, Dana, a Queensland species, 

 and Trapezia ci/modoce, Herbst, a rare form. 



Small individuals of Nepttmus pelagicus, Linn,, were caught, and, with 

 Thalamita prymna, Herbst, represent the Portunidas. The former is one of 

 the edible crabs sold in the Sydney market, and a very widely-distributed 

 species, but does not appear, so far as our observations went, to attain 

 any size at Lord Howe Island. A second small species of Thalamita was 

 collected, covered with many spines, but is at present undetermined. When 

 visiting Blenkinthorpe Bay", Mr. Thorpe and the writer obtained numerous 

 examples of a sand-crab, to all appearance Ocypoda ceratoplitlialma. Dr. W. 

 A. Haswell states* that the hands are not spinous, but in our specimens they 

 are decidedly so, and correspond more closely with the description given by 

 Starkt than they do with that of the other writer. This crab burrows in the 

 sand between tide-marks, to a depth of two feet or more, the burrows running 

 obliquely in a direction from the approaching water. The apertures of these 

 retreats are circular, and at a first glance resemble those of some mollusca. 



The largest crab we met with at Lord Howe was G-rapsus varieijatus, Eabr., 

 and it is without doubt also the commonest. It is a species found every- 

 where throughout the Pacific, reaching even to the coasts of Chili. J Another 

 cosmopolitan member of the Glrapsida) is Planes minutus, Linn., and besides 

 this we found Paragrapsus quadridentatus, M. Edw., and Plagusia cJiahnis, 

 Linn. The identification of the former is open to some doubt, although the 

 females were obtained having the characteristic line down the hand to the 

 forefinger. The latter is another species having a very wide distribution. 



The little Leioloplms planissionus is common under stones, exceedingly 

 quick, and, like some spiders, has the habit, when disturbed, of crouching 

 down with its legs tucked under it, when its almost flat carapace is difficult 

 to detect. ^ 



By far the most important member of the Decapoda was Mr. Whitelegge s 

 discovery of a fresh-water crab, plentifully distributed in the water-carrying 

 gullies of the JSTorth Ridge, beliind the Old Settlement, at a height of from 

 200 to 300 feet above high-water marli;. It is a species of Ilymenicus. After 

 leaving Newcastle in the s.s. " Taupo," on our way to Lord Howe Island, a 

 derelict waterman's wherry was picked up, and in the joints of the timbers 

 and along the keel we found a small crab, probably the larval condition_ of 

 Mycterisdongicarpus, Latr., a species found in Port Jackson, and, according 

 to Dr. Ilaswell, in New Caledonia also. It is frequently met with marching 

 in largo companies over sandy flats. The elegant Banina dentata occurs at 

 Lord Howe, but although at times plentiful enough, we did not succeed in 

 taking it. A specimen was, however, obligingly presented by Mr. W. Nichols. 



* Cat. Austr. Stalk and Sessile-eyed Crustacea, 1882, p. 94. 



t Elements Nat. Hist., 1828, li, p. 148. 



tFish and Fisheries of New South Wales, 1883, p. 125. 



