1 



VKL. 





o]>r*ted from the auU'iuinry pit*. Internal nutoaua) vortical; 

 external autennx occupying the internal aii^le of the orbit, and 

 nearly of the mine form as in (Jrapttu. Anterior bonier of the 

 fnunc very projecting, and continuous with the lower orbital border. 

 The external jaw-feet close the mouth completely, and are not 

 notched within a* in Orapnt ; they arc in form generally very nearly 

 the lame a> in the Crabs and 1'ortunut ; the thinl joint in nmr?i 

 shorter than the preceding one, nearly square, and notched at it* 

 anterior and internal angle for the insertion of the succeeding joint. 

 Sternum very wide and deeply notched backwards for the recaption 

 of the abdomen. Aut.-rior feet generally moderate in the male and 

 small in the female; claws ordinarily with a spoon-shaped termi- 

 nation ; succeeding feet di<t|x>sed an in Grapita ; sometimes the thinl, 

 sometimes the fourth pair longest ; they are in general ciliated on the 

 *u)K-rior border, and the tr.m is always armed with strong spines. 

 Abdomen and braucliiie as in tiraptut. 



Playtuia belongs more particularly to the Indian Ocean, and is 

 found from the Cape of Good Hope to Chili. (M. Edwards.) 



A. Species having the superior border of the last eight feet armed 

 with teeth nearly throughout its length. 



J'. elarimana (Cancer planittimut, Herbst). Length rather more 

 than an inch : antepenultimate ring of the abdomen soldered to the 

 preceding ring in both sexes. It is found in Australia, and Vanicoro, 

 Mew Zealand. 



. rtagiula elarimana. 



B. Species whose lost four pair of feet are not armed above with 

 more than a ainglo tooth placed near the extremity of the upper 

 border of their third joint. 



P. deprena (Cancer deprctsiu, Herbst ; Grajttut dcpreutu, Latrcille ; 

 P. imautculala, Lamarck ; P. drprnta, Latreille). It is a native of 

 the Indian Ocean, seas of China, Xew Guinea, &c. 



M. Milne-Edwards observes that the specific name of this Playutia 

 i* badly chosen, inasmuch as it is less flattened than the greater part 

 of the species. He is also of opinion that P. Jtprenxt of Say (' Acad. 

 Philad.,' torn. i. p. 100) appears to be nearer to P. tquamota than the 

 species here mentioned, but he thinks that it ought probably to be 

 distinguished from it. 



Vnrunn (M. Edwanls). Carapace very much depressed and 

 nearly quadrilateral, but thu lateral borders arched. Front wide, 

 straight, and trenchant. OrbiU approaching to oval ; a fissure on 

 their superior border, their external angle very salient, and hardly 

 any inferior border. Internal antenna bent back a little obliquely 

 outwards, and then- pita completely separated from the orbits by the 

 baiilary joint of the external antenna;, which joins the front, and 

 preaeuts nothing remarkable. Epistome larger than it is in the greater 

 part of the Qrapsoidians, and external jaw-feet nearly joining it ; 

 their internal border is nearly straight, and the third joint, very 

 much dilated externally, carries the following joint towards the 

 imddln of it* anterior border, which in very large and notched. 

 Anterior feet largo ; and the succeeding feet, instead of terminating 

 by a largo and cylindrical or atyliform tarsus, as in the other 

 Orapsoidians, with their Innt joint wide, flattened, ciliated on the 

 edges, and lanceolate. Abdomen of the male with seven distinct 

 joint*. 



V. lilterata (Cancer littcratut, Fabriciui; Grapiui litlcratui, Bosc.). 

 Locality, Indian Ocean. 



I.KI'IS, a genus of Fossil Ganoid Fishes, from the 

 Carboniferous system of Carluke. (Agassiz.) 



M'TO'I.ITHUS (literally writteu-stone '), a name used by 

 UoDMH chiefly to include appearances in stone* resembling drawings 

 as of maps, ruins, vegetable forms, &c. Thu* the Florentine, or 

 Hiiin Marble, the dendritical ramifications on many limestones, and the 

 moss-like form* in agates, tc. were naked as Qraptolite*. 



Among the species included by l.iunicus is one resembling 

 from the Transition Strata of Gothland. 

 <;i:ASSHOl>l'KK. [Ciivi.i. 

 GRASSHOPPER-WABBLER. 



GRATELU'PIA, a gonus of Conchiferous Molltuca, established by 

 M. Charles Di'suioulinx, for a fossil bivalve which had been confounded 

 by H. de Bastcrot with the genus JJuna.r, mi. In- the name of Doata 

 irrtgulan*. But one species, Gratelupia dunaciformit, was known 

 (from Bordeaux, Miocene Formation of Lyell), till Mr. Lea discovered 

 a second in the Claibome Tertiary (Eocene of Lyell), which he ha* 

 named Gratcluiiia, Moulintii, after the founder of the genus. Diameter 

 1 inch, length 1-4, breadth l'. It ha* the following characters: 

 Animal unknown. Shell subtrigonnl, equivalve, regular, 

 <iiuiliitor.il, a little attenuated at it* posterior part, and presenting at 

 the postero-iuferior bonier a slight sinuosity. Umbones very small, 

 projecting but little, and hardly inclined forwards. Hinge consisting 

 of three cardinal divergent teeth in each valve, and of from three to 

 six cartlini-serial teeth converging towards their summit*, lamellar, 

 with their edges finely dentilated, and situated a little behind the 

 .summit, under the ligament; a single lateral anterior tooth un.l.-r 

 the lunule in the left valve, corresponding with a pit similarly 

 situated in the right valve ; external ligament long, convex, over- 

 passing the serial teeth. Muscular impressions nearly equal, oval, 

 united by a pallia! impression largely and very deeply excavated 

 backwards. 



The genus was named by M. C. Desmouliua after Dr. Gratcloup. 



Grntclupia Slmilintii. (Leu.) 



GRAUWAl KE (or Gray wacke, as it is often written in English 

 works on geology), a Gorman term applied to some of the ancient 

 stratified rocks, which has been with some unwillingness admitted by 

 English geologists, either in the original sense, signifying a particular 

 kind of rock, or as typifying a group or series of strata in which such 

 rocks form a conspicuous portion. 



In the former sense Grauwacke Rocks may be considered as having 

 almost the same relation to clay-slates that argillaceous sandstones 

 and conglomerates bear to common clays ; for argillaceous shite, by 

 including rolled fragments or minute grains of quartz-sand, with or 

 without mica, becomes the grauwacke and grauwacke slate of Werner 

 and his followers. When the sand or gravel predominates so as nearly 

 to exclude the argillaceous cement, the distinction between grauwacke 

 and sandstone is almost imaginary, just as, on the other hand, indu- 

 rated shale and soft clay-slate are not always certainly distinguishable. 

 In the pass of Lennie, above Callender, in the Lamir.crmulr Hills, in 

 the primary series of rocks near Cavan in Ireland, and in Suow.loii, 

 the student may study examples of the genuine grauwacke of tlie 

 German writers ; while fine-grained sandy rocks, corresponding t" the 

 title of grauwacke slate, are common in Westmoreland, Cumberland, 

 Wales, the laic of Man, the Lammcrmuir Hills, 4c. . 



Viewed geologically, the Grauwacke Rocks lie in the midst of the 

 primary argillaceous strata, and constitute a part of the 'Iran 

 series' of the continental geologists. The ' grauwacke 

 Sir Henry I>o la Beche includes the Silurian Rocks of Sir Roderick 

 Murchixon, and a portion of the older strata designated as Cambrian 

 Rocks by Professor Sedgwick. [GEOLOOT.] It is uncertain whether 

 the term 'grauwacke' will in future be used merely to characterise 

 rocks of a certain kind lying in the Cambrian or other series of argil- 

 laceous schists, or be allowed collectively to represent a geological 

 group of strata. 



Mr. Conybeare ('Reports of the British Association') is desirous 

 of substituting for this somewhat rude term the more learned name of 

 claimoschist (it\<topa, a fragment). M. Bronguiart inclndi M m my 

 varieties of grauwacke and grauwackc slate under the term psammite 

 (tjxLipor, sand). [GEOLOGY ; i i. \TIKK-ATIOX.] 



ORAVKL. The small fragments of rocks which have been drifted 

 by any forces of water over the surface of the earth are usually 

 designated by this general term, which is happily frco from any 

 hypothetical meaning. Many parts of the surface of the earth are so 

 covered. From the geographical phenomena, mode of accumulation, 

 and other circumstances, the mode of action of the water may be often 

 completely determined. It i* certain that much of the undulated 



