Eucarida — Dc capo da . 5 1 



SuB-oRDKK I.— MACRURA. 



Tlie Macrurti are generally distinguished by the large size of Table- 

 the abdomen, which is symmetrical and not folded under the body, j^^g ]^_j(5_ 

 The front, or rostrum, is not united with the " epistome." Tlie 

 sixth pair of abdominal appendages (uropods) are always 

 present, generally broad and flattened, forming with the telson, 

 a " Tail-fan." 



The first Tribe of tlio Macruru-, tlic Pknaeidea, consists of T.iljle-casc 

 prawn-like animals having tlie first three pairs of legs usually ^ "• ■ • 

 chelate or pincer-like, and not differing greatly in size. The side- 

 plates of the second abdominal somite do not overlap those of the 

 first. Members of this Tribe are the commonest Prawns in tropical 

 seas, and often reach a great size, roiacus carcunote (Fig. 31) is 

 highly esteemed for the table in Mediterranean countries, and 

 manv other species are used for food in various parts of the 

 world. P. carcunote is stated to liave occurred on tlie Welsh 

 coast. Lcucifcr, a delicate, transparent, pelagic form, belong- 

 ing to this tribe, differs from all other Decapoda in having no 

 gills. 



The small Tribe of the Stenopidea includes a few forms which 

 resemble the Penaeidea and tlie Astacidea in having the first three 

 pairs of legs chelate, but differ from them, among other characters, 

 in the fact that the third pair is much the largest. SfcnopKs, a 

 common tropical genus, is remarkable for the brilliant colora- 

 tion of the living animals. The specimen of S. Jiispidiis ex- 

 hibited here has been painted so as to convey some impression 

 of this. 



The Tril)e Caridea includes the true Prawns and Shrimps. 

 The first two pairs of legs are generally chelate or pincer-like, and 

 the first is seldom larger than the second. The second somite of 

 the abdomen has the side-plates ])roadened, so as to overlap those 

 of the somites in front and beliind. 



Only a few of tlie numerous families composing this tribe are 

 illustrated liy the specimens exhibited. 



The nienibers of the family JninlJicjilniriihic are deep-sea 

 animals, and possess many primitive cliaractei'S. Like some of 

 the related families, they have swimming branches (exopodites) on 

 the legs. Some of them are phosphorescent. 



The Nematocarcinidar are also inhabitants of the deep sea, and 

 are remarkal)le for the extreme length and slenderness of the legs, 



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