CRUSTACEOLOGY. 



387 



fewtncea. A. Two processes on each side of the tail. 

 s «— ~y— ' Genus LXV. Anthoura. Tail with two broad 

 lamella; on each side, and a middle process ; antenna; 

 short, the upper pair longest. Anterior pair of feet 

 furnished with a moveable hook. 



Genus LXVI. Cymothoa. Tail composed of ma- 

 ny segments ; the body not rolling into a ball ; the feet 

 armed with strong nails. 



Genus LXVII. Sph.eroma. Tail composed of two 

 segments ; body capable of rolling into a ball ; the tar- 

 sal nail of a moderate size. 



B. One process on each side of the tail. 



Genus LXVIII. Nes^ea. Peduncle of the superior 

 antenna; large, and long; body six -jointed, the last joint 

 1 argest. 



Genus LXIX. Campecopea. Peduncle of the su- 

 perior antennae not large, but longer than the inferior ; 

 the process at the side of the tail long and curved. 



II. The four antennae obscure or wanting. 



Genus LXX. Bopyrus. 



Family XIX. Oniscides. 



The internal antennae very short and obscure. 



Genus LXXI. Ligia. External antennae termina- 

 ted by an articulated seta. 



Genus LXXII. Philoscia. External antennae eight- 

 jointed ; the base naked ; the first joints of the tail 

 abruptly narrower than the last joints of the body. 



Genus LXXIII. Oniscus. External antennas with 

 eight joints, inserted under the margin of the head. 



Genus LXXIV. Porcellio. External antennae with 

 seven joints, inserted under the margin of the head ; 

 lateral styles of the tail conical and projecting. 



Genus LXXV. Armadillo. External antennae with 

 seven joints, inserted in a fovea, in which the margin is 

 elevated; lateral styles of the tail not projecting, ter- 

 minated by a triangular joint; (body capable of rolling 

 into a ball.) 



TRIBE II. MILLEPEDA. 



Feet above fourteen. Antennae two. All the seg- 

 ments of the body, the anal, and head excepted, bear- 

 ing feet. 



Family XX. Julides. 



Palpi 



The maxillae adhering to the lip, or wanting, 

 teuberculiform and obscure. 



* Body crustaceous. 



Genus LXXVI. Glomeris. Body elliptical, convex 

 above, arched beneath ; rolling itself into a ball when 

 touched. 



Genus LXXVII. Julus. Body oblong; eyes gra- 

 nular, and very distinct. 



Genus LXXVIII. Polydesmus. Body long; eyes 

 obscure. 



** Body soft. 



Genus LXXIX. Pollyxenus. Body oblong, ter- 

 minated by a pencil. 



Family XXI. Scolopendrides. 



Two very distinct maxillae, connected at their base. 

 Maxillary palpi two, which are filiform. Labial palpi 

 also two in number, terminated by a little hook (ha- 

 mulus.) 



I. Each segment bearing two pair of feet. 

 Genus LXXX. Scutigera. 



II. Each segment bearing one pair of feet. 

 A. Antennae coaico-setaceous. 



* Feet forty-two. 

 Genus LXXXI. Scolopendua. Eyes eight, 

 Genus LXXXII. Cryptops. Eyes obscure. 



** Feet thirty. 

 Genus LXXXIIL Litiiobius. Eyes granular. 

 B. Antenna; filiform. 

 Genus LXXXIV. Geopiiilus. 



Crustacea. 



ORDER I. ENTOM08TRACA. Bntohos* 



TRAcA. 



Family I. Xiphosura. 



oenera and 



Genus I. Limulus. Shell coriaceous, of a rounded l. Lmuius. 

 oval form, rather narroAver behind than before, notch- 

 ed and flattened. Clypeus double. Shell divided, the 

 anterior division the largest, somewhat moon-shaped, 

 with three elevated ridges on the back. Eyes two in 

 number, small, oval, and obscure, placed on the under 

 side of the carina; or ridges. Back -carinated, with a 

 deep sulcus or groove on each side. Tail horny, at- 

 tached to the body by a hinge-like joint. No antennae. 

 Two double jointed, cylindrical mandibules, situated / 



on the under part of the anterior division of the shell ; 

 the outermost digitated, furnished with a finger and 

 thumb, the former being moveable. Feet ten, all (ex- 

 cepting the anterior pair, which are most frequently 

 simple,) furnished with a finger and thumb. The bran- 

 chiae, or gill-like lungs, situated under a horny lamella 

 on the sides of the body. 



Sp. 1 . Polyphemus. All the feet digitated ; tail three- Polyphe- 

 sided, frequently somewhat notched above ; the middle mus - 

 carina of the anterior scutum spiny. 



Inhabits the ocean of South America, where it is well 

 known to sailors under the name of king-crab. 



Monnculus polyphcmus of Linne. 



Limulus cijclops of Fabricius. 



Sp. 2. Moluccanus. All the feet digitated; tail three- Mo!ue- 

 sided, notched above from the base to the apex. The canus. 

 middle carina of the scutum without spines. 



A native of the East Indian ocean. Latreille, Gen. 

 Crust, el Ins. torn. i. p. 11. — Molucca crab. 



Sp. 3. Hcterodactylus. The four anterior feet simple. Heter.i- 



dactylus, 

 Lat. Hist. Nat. des Crust, et 



Inhabits China. 



Limule heterodaclyle. 

 des Insect, torn. iv. p. 89. 



Limulus hcterodactylus of Latreille's Genera Crust, 

 et Ins. 



Sp. 4. Virescens. The anterior pair of feet simple. Virescens. 



Inhabits the East Indian seas. 



Limulus polyphcmus of Fabricius. 



Observation. Limulus noctilucus, discovered by Cap- 

 tain Horsburgh, and described by James Macartney, 

 Esq. in an ingenious paper on luminous animals, Phil. 

 Trans. 1810, Plate xv. p. 292, evidently belongs to a 

 distinct genus, at present unknown to us. 



Family II. Pneumonura. 



Genus II. Caligus. Shell heart-shaped. Two eyes 2. Calisus 

 placed at a distance from one another, on the anterior 

 mai-gin of the shell. Antennae minute, setaceous. 

 Mouth with a conic rostrum, winch is bent downwards. 

 Feet either eight or ten ; two or four of which are fur- 

 nished with an inflexed nail, and are formed for walk- 

 ing ; the pair following these walking feet are armed 

 with setae, (sometimes with a double nail,) the rest 

 bearing leaf-like lamellae. Abdomen exscrted, and par- 



