Royal Physical Society of Edinburgh. 3839 



animals respectively diurnal and nocturnal in their habits. Hyas coarctatus must be 

 common between Gullaneness and Largo, judging from the hundreds that are brought 

 up by the trawl; but it rarely occurs above this. Dr. H.'s observations coincide with 

 those of Mr. Bell in regard to the disparity in size between the male and female ; 6£ 

 inches is not uncommon for the span of the male acoss the third pair of limbs, whereas 

 the largest female met with by Dr. H. had only a span of 3£ inches at corresponding 

 parts. Eurynome aspera is probably not uncommon on mud in five or seven fathoms 

 off Prestonpans and Portseaton. It is very apt to be overlooked, as it is generally in- 

 crusted with minute Algae and mud, and in that state resembles the young of Hyas 

 araneus. Portumnus variegatus appears to be rare : Dr. H. found one small living 

 specimen* on the sands between Musselburgh and Prestonpans two years ago ; and 

 Lieutenant Thomas obtained two cast shells at Portseaton last October. Portumnus 

 marmoreus is occasionally thrown on the beach at Portobello and Musselburgh. Por- 

 tumnus pusillus is very plentiful in mud off Prestonpans. Portumnus depurator is 

 common everywhere. Corystes cassivelanus is believed to be frequently cast ashore at 

 Portobello after storms. Lithodes Maia is familiar to most of the fishermen engaged 

 at the mouth of the Firth ; but it is probably very local, and an occupant of deep 

 water. Of the small Paguri, the most common and best-marked species is Pagurus 

 Hyndmanii ; it is at once distinguished from all the others by the length of the se- 

 cond joint of the inferior antenna?. Dr. H. found it common in from three to twelve 

 fathoms, off Musselburgh and Prestonpans. Along with the preceding Pagurus leevis 

 occurs, though sparingly. Besides these, Dr. H. has two mutilated specimens, which, 

 however, are characteristic enough. The one appears to be Pagurus ulidianus, the 

 other Pagurus Forbesii of Bell. Porcellana platycheles may be found, although not 

 plentifully, under stones at low water, between Crail and Fife-ness ; within a stone's 

 cast, however, round the corner, in St. Andrew's Bay, it abounds in great numbers : it 

 is also believed to be common on the Berwickshire coast. While Porcellana longicornis 

 is very abundant in the upper part of the Firth, it is comparatively scarce where the 

 former species occurs. Galathea squamifera is common under stones at low-water 

 mark of spring tides, on rocky coasts, as at Prestonpans, Portseaton, and Crail. It 

 is occasionally brought up by the dredge, but these specimens are much smaller and 

 lighter in colour than the littoral ones. Galathea strigosa is obtained in deep water 

 near the Bass, &c. Galathea nexa is frequently dredged in mud, in from three to 

 twelve fathoms, between Seafield and Portseaton. Munida Kondeletii must be rare 

 in the Firth of Forth ; Dr. H. is aware of only one instance of its occurrence, namely, 

 to Mr. R. Gray, at Dunbar. Nephrops Norvegicus is frequently brought up by the 

 line-boats from deep water ; also in the trawl from Largo Bay. Crangon vulgaris is 

 common on all sandy beaches ; it is the only species Dr. H. has yet met with. Hippo- 

 lyte vulgaris is very common in pools at low water at Prestonpans, Portseaton, Crail, 

 &c : the variation in colour in different specimens is remarkable, and generally agrees 

 with the colour of the prevailing sea-weed in these pools. Sometimes it assumes the 

 precise hue of Laminaria or Delesseria, at others it is dark green, or light green, or 

 bright red, as the case may be ; and the colour does not disappear at death, but re- 

 mains for months after. In the crab-pots at Crail Dr. H. found several specimens of 

 Hippolyte which apparently differ from any of the described British species. It bears 

 some resemblance to Hippolyte Cranchii of Leach, but has the rostrum shorter, more 

 depressed, and not bidentate at the apex, as in that species. The wrist of the second 

 pair of limbs is composed of seven articulations instead of six : and the central plate 



