232 Notes, iv. 8. 



moreover, though readily bruised or crushed, not being brittle like that of Testacea 

 {H. A. iv. I, 3 ; iv. 2). There are, he says, four main genera : I, Carcini ; 2. Carabi ; , 

 3. Astaci ; 4. Carides. The first three are decapodous ; the Carcini having no tail but 

 a flap, while the remaining two have long tails. This identifies the Carcini with our 

 Brachyura, or crabs. The Astaci are said to have the anterior pair of feet converted 

 into strong claws, of unequal size and differently toothed ; the second and third pairs 

 of feet being also chelate. Their shell is smooth, and some of them live in freshwater. 

 There is no difficulty in recognising in this description the lobster {Asfacus tnarinus) and 

 the river crayfish (Astacus fluviatilis). The Carabi differ from the Astaci in having 

 a rougher shell, larger eyes, longer and stouter antennae, a narrower thorax, and a harder 

 and less fleshy body. They differ also in the character of the first pair of feet. In the 

 Astaci these are chelate in both sexes ; but in the Carabi only in the female. On this 

 last point, however, A.'s language is not always quite consistent. For in the text he 

 speaks of the Carabi as always having claws like the crabs. This description leaves no 

 doubt that the animals meant are the spiny lobsters {Palinurus vulgaris). Although 

 the anterior feet of these animals never form such perfect claws as those of Astacus, 

 yet the terminal joint bends over and meets a process from the penultimate joint, so as 

 to make a nipper. This process is developed in very different degrees of perfection in 

 different individuals, as I have myself noticed, and thus it is easy to understand how 

 at one time they might be described as having claws, at another as without them. 

 Whether there is any difference in this respect dependent upon sex, I do not know. 

 There remain the Carides. These are said to have a tail, like that of the Carabi, no 

 claws, and more than five pairs of feet. The name would thus appear to designate 

 some of the Amphipoda, and Stomapoda. A. describes two kinds ; his account in 

 one case suiting the sea-mantis {Squilla mantis), but in the other being insufficient for 

 positive identification. As to the separation of Crustacea from Insecta, see iv. 6, Note I. 



2. The Maia is said (H. A. iv. 2, 3) to be the largest of the cral:>s, the next in size being 

 the Paguri and the Heracleotic crabs, and to have a hard shell (^. A. viii. 17, 11). 

 Again (ff. A. iv. 3, 3) the Maia and the Heracleotic crabs are said to have their eyes 

 placed close together, near the median line. Here we are told that the Maiee have thin 

 legs, the Heracleotic crabs short ones, and that both live out at sea. From these passages 

 Cuvier and most writers have concluded with great probability that the Maia answers 

 to the Maia Squinado or spiny spider-crab, the largest of the crabs common in the 

 Mediterranean. There are no data to determine what are meant by the " Heracleotic 

 crabs." 



3. In most crabs the four hinder pairs of feet are formed exclusively for nmning ; but 

 in some few they are flattened out so as to serve in swimming. These swimming crabs 

 are all small. Rondelet mentions several species as found in the Mediterranean. 



4. Cf. ii. 9, Note 9. 



5. A. does not explain why an animal that swims should want more legs than one that 

 has any other mode of progression ; and the statement that it does so is somewhat in 

 opposition with his previous remarks about Myriapoda. Probably he has in his eye the 

 image of a ship with its numerous oars on either side. 



6. "In the Podophthalma, the lamelliform ciliated appendages of the abdominal 

 segments include similar marsupial or incubatory recesses for the ova. The female lobster 

 and other Macrura are distinguished from the male by the greater development of these 

 appendages" {^Owen's Led. i. 185). Similarly Cuvier {Reg. An. iv. 28), speaking of the 

 flap or tail of the Brachyura, says, " Triangulaire dans les males et gamie seulement 

 a sa base de quatre ou deux appendices, elle s'arrondit, s'elargit et devient bombee 



