167 MAIIDJS. 



OAorimu (Leach). Carapace longer and narrower than it is in 

 nearly all of the Maiidtt ; but in general form not differing much 

 from Pita. Rostrum formed of two great pointed horizontal horus. 

 Eyes retractile, and the orbits directed outwards and downward* ; 

 but the lower wall of these cavities is very incomplete; basilary joint 

 of the external antenna narrow, their moveable stem inserted under 

 the rostrum, and in great part concealed by it. Epistome, jaw-feet, 

 sternal plastron, and abdomen, disposed nearly as in Pita ; anterior 

 feet longest, especially in the males, and the claw strongly curved 

 inwards, dentilated and pointed, but a little hollowed out into a sort 

 of gutter; the succeeding feet are cylindrical ; those of the last three 

 pain of moderate length, but the second pair are very long : in the 

 male they are in general once and a half or even twice as long as those 

 of the third pair. 



M. Mime-Edwards divides the species of this genus into two 

 lections : the first consisting of those which have the superior orbital 

 border scarcely marked, and formed by three spines, the anterior one 

 very Urge, and the two posterior rudimentary ; the second consisting 

 of those species which have the superior border lamellose and 

 advanced. 



C. Uarot is the only species of the first section. Length from two 

 to three inches, or rather more. Rostrum, sides of the carapace, and 

 four hsl pair of feet, hairy. Colour yellowish-red. 



It is taken in the seas of the Antilles 



Chorinta Ittra, reduced onf-ha'f. 



ItMrax (Leach). Carapace always a little convex above, and a 

 ^ood deal narrowed forwards; disposition of the different regions as 

 in the other Oxyrhynchs ; rostrum bifid, generally very short, and 

 separated from the internal canthus of the eyes by a rather consider- 

 able space ; orbits nearly always armed with two or three spines at 

 their superior border, one at their external angle, aud one or two at 

 their inferior border ; latero-anterior borders of the carapace spiny, or 

 at least toothed ; internal antenna; bent a little obliquely outwards, 

 and the frontal portion of the partition which separates them armed 

 with a recurved spine ; basilary joint of the external antenna; large, 

 and nearly always armed forwards with two strong spines ; the second 

 joint of these appendages is, on the contrary, narrow and cylindrical, 

 and inserted on the sides of the rostrum, nearer the antennary fosset 

 than the orbit ; third joint nearly as large and as long as the second ; 

 the terminal and articulated stem rather short. External jaw-feet 

 presenting nothing remarkable ; sternal plastron nearly circular ; ante- 

 rior feet generally in the male longer and stouter than that of the 

 second pair, the band or claw always stout and convex, the pincers 

 distant at their base, enlarged at the end, deeply hollowed into a 

 spoon-shape, and terminated by a semicircular treuchaut cdtte ; feet 

 of the second pair about once and a quarter as long OH the post-frontal 

 portion of the carapace ; the succeeding feet gradually shorten' <1 ; t li- 

 tarsi short, booked, and often armed with some point* at their inferior 

 surface. Abdomen generally formed of seven joint* in both sexes ; 

 but sometimes only four are to be perceived in young females, the 

 second, third, fourth, and fifth segments being soldered. 



M. Milne- Kd wards remarks that Mithrax estnhliidm some connection 

 between the family of the Oxyrhynchs and that of the Cyclomctopes. 



The specie* are found In the teas of America fur the most part, 

 where some of the species attain to a considerable size. 



M. Milne-Edwards divides the genus into two sections : the first 

 consisting of those species which have the superior edge of the orl.it 

 armed with strong spines; the second, of those which have the supe- 

 rior border of the orbit unarmed. The first of these sections is 

 further subdivided into two sub-genera, the first sub-genus consisting 



MA1ID.S. m 



of those triangular species whose last four feet are not spiny ; and the 

 second sub-genus, of those transversal species whose last four feet are 

 armed with spines. The second section contains the third sub-genus, 

 consisting of the depressed species. 



M. dichotomtu is about two inches in length. Colour, yellowish. It 

 is found on the coasts of the Balearic Island*. 



Mithrax dicfiutomtu. 



a, under part or the bead ; 6, abdomen of tbc male ; c, termination of one of 

 the posterior feet. 



Paramithrax (Milne-Edwards) Establishing, in the opinion of M. 

 Milne-Edwards, the passage between Mithrax and Maia. 



General form of the carapace very closely approaching that of the 

 triangular Milhracet. Rostrum formed of two stout horns, and consi- 

 derably less wide than the front, which, in its turn, has nearly as 

 much extent as the buccal frame. Orbits oval-shaped, their upper 

 border arched forwards as in the Maia;, and with three strong spines 

 posteriorly separated by two notches more or less deep ; their inferior 

 border widely notched or incomplete. Eyes retractile, with slender 

 peduncles, which are rather long and recurved, as in the Maia. The 

 antennary region and antennary pits resembling those of the Maite. 

 Basilary joint of the external antenna) large and armed with spines, 

 one of which (the external) advances in general beyond the border of 

 the front, and separates the orbit from the insertion of the moveablo 

 stem, which is not covered by the front. External jaw-feet and 

 sternum nearly as in the Maia. Anterior feet of moderate strength, 

 and terminated by pointed and rounded claws, which are not dentilated 

 as in Pita, nor hollowed into a spoon-shape as in Mithrax. The suc- 

 ceeding feet are cylindrical, very little or not at all spiny, and of 

 variable length, according to the species ; there are no miml! horny 

 points nt the lower end of the last joint, as in most of the Mithracti. 



The species are Australasian. 



M. Milne-Edwards divides Paramithmjc into two sections : the 

 first consisting of those species which have the orbits very incomplete 

 below, and whose eyes do not reach to the external angle of the 

 cavities ; the second, of those whose orbits have only one notch below, 

 and whose eyes, when turned back, touch the external orbital angle. 

 P. Peronii is an example of the first section, aud P. Oaimardii of the 

 second. 



Maia (I.amarck). This genus was established by the author of the 

 ' Animaux sans Vertebras,' for the reception of the genera /nachtut 

 and Parthenope of Fabricius, or, in other words, for all the Ofyrhynehi 

 properly so called. More modern authors have cut the Laiuarckian 

 genus down to the group formed by the small number of epecies which 

 may be arranged in close approximation to M. ,^/iiinndo. 



Carapace about a fourth longer than it is wide, and much narrowed 

 anteriorly ; its upper surface is rough, with multitudinous tubercles 

 and spines, and the regions are not strongly marked on it ; rostrum 

 horizontal, and formed of two divergent horns; the latero-anterior 

 Ixirder of the carapace armed with strong spines ; orbits of an oval 

 chape, rather deep, and with their superior border, which is elevated 

 and rounded anteriorly, divided behind by two fissure*. Internal 

 antenna; exhibiting nothing remarkable, but the portion of the front 

 which separates their fossets or pits is prolonged into a strong curved 

 Kpine, which is directed downwards. First joint of the external 

 antenna: very large, and constituting more than half of the inferior 

 floor of the orbit, which it only exceeds anteriorly a very little ; its 

 extremity is armed with two stout spines, and carries the succeeding 

 joint at its superior and external bonier, so that the moveable stem of 

 these appendages springs in the internal canthus of the eyes. E pis tome 



