T H A 



277 



T H A 



fin is composed are wide and rounded. The thoracic 

 bntnchicc are enclosed as ordinarily in the carapace, and are 

 each composed of cylinders ranged in parallel order on a 

 stem, nearly as in the lobsters, only these organs and fila- 

 ments are less numerous, and the branchiae themselves very 

 small. There are only ten on each side of the body. (M. E.) 



Example, Calliahidea typa. Length about 10 lines. 



Locality. Coasts of New Ireland, where it was found 

 by MM. Quoy and Gaimard. 



CallianiJca lypii, magnified. " 



rt, antenna nf the first pair; 6, exU-iual j.iw-foot; c, extremity of one of 

 (Ve jtmierior feet; d, abdominal false feet, first pair; e, fa!-i- u'ct of ooe of 

 tin- f >ur succeeding pairs ; /, marginal fiiutfe of those false ft-et. 



So much doubt exists relative to the genus hen, Guerin, 

 (,'al/ianixea, M. Edwards, that we think we should not be 

 justified in occupying space witli the very lontr and elaborate 

 .ption of M. Guerin, and the acute criticisms of M. 

 Milne Edwards, who observes that Ixr-n, having been pre- 

 viously employed to designate another crustaceous animal, 

 cannot be retained. M. Guerin's description will be found 

 in the ' Annales de la Socic'-W Entomologique de France,' 

 torn, i., p. 295 ; and also in M. Milne Edwards's ' Histoire 

 Nahirelli.' dcs CrustaeeV torn, ii., p. 322. But though our 

 limits do not permit the insertion of the details, they 

 should be carefully perused by the student, for they are 

 highly interesting ana instructive. 



FOSSIL THALASSINIANS. 



M. Milne Edwards states that the erustaceous fossil found 

 in the chalk formation of Maastricht, and figured by M. 

 Desmarest under the name of Pagurus Favjasii, belongs 

 to the genus Ca/tin>/ti\.iii. 



THALASSIO'KMS, Mr. Eyton's name for one of the 

 cluck* '.Smith, subfamily Erismuturiitep. 



THAI ASSIOPHYTKS 'literally 'sea-plants,' from dd- 

 \aaaa and I/IVTOV, is the name given by Lamouroux to desig- 

 nate the vegetable productions of the ocean and of its rocks 

 and shores. It is equivalent, fo the term Hydrophytes of 

 Lingbye, and the plants described by Agardh as Marine 

 Algae. This division of the vegetable kingdom compre- 

 hends, in Lamouroux's system, six orders, viz., Fucaceae, 

 Florideae, DictyoUse, Ulvacea-, Aphlomideae, and Phlo- 

 midese. [SEA-WEEDS; ULVACE.E.] 



THALKS it./Xijs) was a native of Miletus, one of the 

 chief cities of Ionia, and descended from a Phoenician 

 family. Apollodorus, as quoted by Diogenes Laertius, 

 fixes the year of his birth in the first year of the 35th 

 Olympiad, or B.C. 640. Herodotus (i. 74) says that Thalcs 

 the Milesian predicted the year of the great eclipse which 

 took place while the armies of Cyaxares and Alyattes 

 king of Lydia were engaged in battle. Alyattes became 

 kin!; of Lydia in B.C. 617. Herodotus also says (i. 75) 

 that Thales was in the army of Croesus at the time of the 

 battle ofPteiie between Croesus and Cyrus B.C. 547 or 

 5-16 ; at which time he would be ninety-four years old, if 

 the date of his birth is correctly given by Apollodorus. 

 Th-re was a general tradition that he lived to a great age ; 

 and Luciaii states that Solon, Thales, and Pittacus all 

 lived to be a hundred years old. (On the subject of the 

 ecl'.ps,-! see the articfc ALYATTES, and Oltmanns, Ab- 

 hanMungtn der Akad. Berlin, 1812-13.) 



In the Life of Thales by Diogenes we find numerous tra- 

 ditions attached to his name, the value of which it is some- 

 what difficult to estimate. Thales is enumerated among 

 the Seven Wise Men, whose wisdom was not the theo- 

 retical wisdom of philosophers, but the wisdom of actual 

 life. [BIAS.] Accordingly we find that Thales took an 

 active part in the political affairs of his native country. 

 Before Ionia fell under the Persian yoke, he advised the 

 lonians to have one common council, and to establish it 

 at Teos, for Teos was in the centre of Ionia ; and he fur- 

 ther suggested that all the other Ionian states should be 

 reduced to the condition of parts dependent on the go- 

 vernment at Teos. Such a scheme, if carried into effect, 

 might have checked the progress of the Persian arms 

 (Herod., i. 170.) Later writers say that he visited Egypt 

 and Crete in order to improve his knowledge, and that he 

 derived from Egypt his acquaintance w'ith mathematics. 

 There seems no reason for thinking that Thales left any 

 writings. Aristotle at least was not acquainted with any 

 philosophical writings by Thales. Various sayings of 

 Thales are recorded : they are of that sententious charac- 

 ter which belongs to the proverb, and they embody truths 

 such as the general experience of mankind recognises : 

 and for this reason they cannot safely be considered as 

 the product of any one mind. Thales is generally con- 

 sidered the founder of the Ionian school ; but it is per- 

 haps hardly proper to consider him in any sense as the 

 founder of a school. [IONIAN SCHOOL.] His traditional re- 

 putation rested on his physical discoveries and his philo- 

 sophical speculations. He is said to have been the first 

 astronomer (among the Greeks) who predicted eclipses ; 

 and to have discovered the passage (irdpolot} from tropic 

 to tropic, or, in other words, to have laid down the sun's 

 orbit : and to have fixed the length of the year at 365 days. 

 He determined the magnitude of the sun to be 720 times that 

 of the moon ; which is apparently the true version of the 

 corrupt passage in Diogenes. His knowledge of geometry 

 was said to be derived from Egypt, and Pamphila attibutes 

 to him the discovery of the right-angled triangle of the circle 

 (wpwrov Karaypa^ai KVK\OV TO rpiywvov opQoyti)vtov\ which 

 probably means the demonstration that the angle in a semi- 

 circle is a right angle, a discovery attributed also to Pytha- 

 goras. Hieronymus says that he measured the height of 

 the pyramids of Egypt by observing the shadow which an 

 object cast when it was of the same length as the height of 

 the object. 



The philosophical speculations of Thales, like the earliest 

 efforts of philosophers in all countries, were an attempt to 

 solve the problem that admits of no solution the real 

 nature of the universe. He is considered by modern 

 writers as the originator of the dynamic philosophy, the 

 nature of which, as opposed to the mechanical, is explained 

 in the article IONIAN SCHOOL. Aristotle (Metaph., i. 3) 

 has explained in a short passage the general doctrine of 

 Thales : 'There must be,' observes Aristotle, 'some Nature 

 (0i1c), either one, or more than one, to which all other 

 things owe their origin, this one still subsisting. The 

 number however and the character of such a first principle 

 are not conceived by all in the same way. Thales, the 

 founder of this philosophy, says it is water, and accord- 

 ingly he (aught that even the earth reposes on water, 

 founding this notion probably on the observation that the 

 nourishment of all things is moist, and that heat itself 

 proceeds from water, and that animals live by it : but 

 that from which things come is the origin of all things. 

 He was thus led to this notion, and also by observing that 

 the seeds of all things have a moist nature, and that water 

 is the origin of their nature to all moist things.' Thus the 

 universe contained an active principle by the power of 

 which all things were developed. He considered that the 

 magnet had life, because it attracted iron. The universe 

 then was pervaded by life, or, as Thales expressed it, 'full of 

 gods' (iravra tt-Xt/pij Sfuiv). 



The doctrine of Thales bears some resemblance to 

 systems that have been promulgated in modern times, 

 which have been viewed as atheistical. The assumption 

 of an active power, such as gravitation for instance (though 

 it is not here meant to affirm that gravitation has ever 

 been viewed as a power sufficient for the production and 

 conservation of all things), which is sufficient to maintain 

 all things in a permanent condition (changes such as we 

 observe in limited portions of time and being only con- 

 tinued developments), may be viewed as an .hypothesis 



