169 



PALEMONID^E. 



TALEMONID^E. 



170 



Pnlemon 



A A. No second spine situated at the base or behind that with 

 which the anterior border of the carapace is armed on each 

 side. 



P. Gaudichaudi, a native of Chili, is an example. * 



The other tribes of Milne-Edwards' 4 Salicoques are the Alpheans 

 and Penxans (Alpheadce and Pciutadce). 



Alplaadue. The shrimps comprised by M. Milne-Edwards under 

 this tribe are stouter in their forms than those of the preceding 

 division, but they are not depressed as the Crangons are. [CRAXGO- 

 SID/E.] The rostrum is very short, and has never the form of a great 

 projecting central blade, a? in the Palemonians. The internal antenna: 

 are placed above the external antenna;, and are, in general, very short 

 One pair of feet is very stout, and generally terminated by a powerful 

 didactylous hand. The two anterior pairs of feet are nearly always 

 'licli'-tylotis, but the third pair never are ; the three last pairs are 

 rather robust, and serve for walking as well as for swimming. 



The genem are Atya, Hymenocera, Alpheiu, Pontonia, Autonomea, 

 C'aridina, iVi'to, and Alhanae. 



Atya (Leach). [ATT A.] 



lli/mcnocera (Latr.). [HtMEXOCERA.] 



Alfiheu* (Fabr.). Carapace advanced above the eyes, forming above 

 each of those organs a small vaulted buckler. Rostrum very small, 

 and sometimes wanting. In other respects the carapace presents 

 nothing particular. The superior antenna) are small, their first joint 

 short, and armed externally with a lamina, which is ordinarily spini- 

 form ; the two next joints are cylindrical ; and of the terminal fila- 

 ments, two in number, the upper one is stouter and shorter than the 

 lower, and presents traces of a division near the end. The inferior 

 antetime are inserted externally to and below the preceding : the 

 lamellar palp is of moderate size, or even sometimes small and pointed, 

 and their terminal filament presents nothing particular excepting that 

 it is often somewhat compressed. The mandibles are provided with a 

 short palpiform appendage, which is wide and flattened. 



They are found in the seas of warm climates. Some species are 

 found in the Mediterranean, but the greater part in the seas of the 

 Antilles or in the Indian Ocean. 



M. Milne-Edwards separates the Alpheans into the following sections 

 and subdivisions : 



1. Species with a pointed rostrum. 



A. No spine at the outside of the basilary joint of the external 



antenna;. 

 Ex. A. ruber, from the Mediterranean. (Milne-Edwardi.) 



B. A great spine fixed on the external border of the basilary 



joiht of the external antenna;, and directed forwards. 

 Ex. A. villotut, from the seas of Anstralin. 



2. Species deprived of a spiniform rostrum. 

 Ex. A.fmntatii, from the coasta of Australia. 



M. Milne-Edwards records twelve species of Alp!ieu. 



mia (Latr.). Carapace short and convex : the front with a 



short but robust and inflected rostrum ; the eyes are cylindrical, pro- 

 jecting, and very moveable. The internal antennae are very short, and 

 formed very nearly like those of the Palemons or Prawns ; the first 

 joint of their pedicle is very wide and lamellar externally ; the two 

 succeeding joints are small and cylindrical. The terminal filaments, 

 two iu number, are very short, and the one between them is bifid at 

 the extremity. The external antennae are inserted above and external 

 to the preceding ; their lamellar appendage is large and oval. 



M. Milne-Edwards divides thePontonice into the following sections : 



1. Species with the rostrum very large and depressed, and the 



external antennae inserted nearly on the same line as the 

 superior antennae. 



Ex. P. macrophtlialma, from Asiatic seas, where it was found by 

 M. Dussumier. 



2. Species with the narrow rostrum very much compressed 



laterally, and inflected towards the point; the external 

 antennae inserted entirely below the superior antennae. 



Ex. P. armata, from New Ireland, where it was found by Messrs 

 Quoy and Gaimard. 



Autonomea (Risso). Antennae intermediate or superior, terminated 

 by two filaments, one of which is much longer and thicker than the 

 other ; external or inferior antennae longer than the body, and seta- 

 ceous. Peduncles of the first inarticulate, having their lower portion 

 convex and armed with a spur, the intermediate long and cylindrical, 

 and the last short and bent. Those of the second bi-articulate, without 

 scales, their second portion being hairy at its extremity. 



Ex. A. Olivii. It occurs in the Adriatic Sea, and rather rarely at 

 the environs of Nice, where it lives solitary in the sea-weed and muddy 

 places ; the female carries her reddish eggs about the middle of the 

 summer. (Desm.) 



Caridiaa (Milne-Edwards). Carapace presenting nothing particular 

 and terminating by a lamellar rostrum varying in length. Eyes pro- 

 jecting. Internal antenna; very long, and terminated by two large 

 multi-articulate filaments, one of which is convex at its base ; external 

 antennae formed like those of the Palemons. 



Ex. C. Typut. 



Nika (Risso). M. Milne-Edwards observes that this genus is remark- 

 able for the defect of symmetry in the conformation of the first two 

 pairs of feet. In their general form, he remarks, they resemble the 

 Palemons, or rather the genus Athanas, for their rostrum is very 

 small Their internal antennae are slender, and terminated, as in 

 these last, by two rather long filaments. The external jaw-feet are 

 pediform, long, and stout ; the joint which terminates them is pointed 

 at the end. The anterior feet are stronger than those which succeed, 

 but of moderate length ; the anterior right limb has a well-formed 

 didactylous baud, whilst that opposed to it is monodactylous and 

 formed after the manner of ambulatory feet. The second pair of feet 

 are filiform, and terminated by a small pincer, which is nearly rudi- 

 mentary ; their carpus is multi-articulate, and their length very d iflerent : 

 the left is nearly twice the length of the anterior feet, and the right is 

 nearly twice the length of its opposite. The succeeding feet are mono- 

 dactylous, and terminated by a styliform tarsus, which is not spiny : 

 the fourth pair are longer than the third. The abdomen has the same 

 form as in the Palemonians. 



N. edulis has the rostrum slightly inflected, and nearly, of the length 

 of the eyes. A small tooth on each side, on the anterior border of the 

 carapace, below the insertion of the eyes. Length about 2 inches. 



It is an inhabitant of the Mediterranean and the English Channel. 

 Mr. Bell regards this species as identical with 1'rocepa canaliculata of 

 Leach. He also describes a second British species, A'. Couchii. 



Athannt (Leach). Carapace not elevating itself into a carina at the 

 base of the rostrum, as in the Palemouians ; the rostrum itself not 

 toothed on its edges. Eyes projecting but little, but not covered by 

 the carapace, as in Alpheus. Internal antennae rather large, and termi- 

 nating by three multi-articulate filaments, disposed as in Palemon, as 

 are the external antenna; also. Mandibles robust, with a palpiform, 

 short, but very Inrge appendage composed of two joints. 



A. nitescem has the rostrum sharp, shorter than the peduncle of the 

 internal antennae ; a spine on each side of its base, on the anterior 

 border of the carapace. Hands unequal, convex, and with short and 

 obtuse fingers. Carpus of the second pair of feet divided into five or 

 six joints. Length about an inch. 



It is a native of the coasts of France and England. 



In the Pettceada, or Penacans, M. Milne-Edwards comprises those 

 shrimps whose abdomen is in general extremely elongated, and whose 

 feet often carry at their base a palpiform appendage more or less 

 developed. The rostrum is short, or nearly null, and the lower 

 antenna;, if not both pairs, are nearly always very long. The con- 

 formation of the feet varies much; but generally these organs become 

 for the most part so slender and long, that they cannot serve except 

 for swimming, and sometimes the last pairs become rudimentary or 

 disappear. 



Genera Stenopui, Sicymia, Penaus, Enphcma, Epkyra, Oplophorus, 

 Patiphma, Sergetta, and Acetet. 



Stenoput (Latreille). Body not compressed laterally, and teguments 

 comparatively soft. Carapace terminated anteriorly by a small rostrum. 

 Eyes short, and disposed in the ordinary manner. Peduncle of the 



