812 



TRILLIUM TRING A. 



chiefly annuals. It is allied to the clovers, and 

 consequently belongs to the natural order Lcgu- 

 minosce. A few of the species are British, and the 

 rest are distributed over Europe and north-western 

 Asia. 



TRILLIUM (Linnaeus). A very curious genus 

 of North American tuberous-rooted herbs, bearing 

 showy hexandrous flowers, and belonging to Melan- 

 thace&(Hort. Brit.), or Smilaceez, according to Sweet. 

 They require to be planted in a shady peat-earth 

 border ; they increase but slowly by division. 



TRILOBITES. A very extraordinary tribe of ex- 

 tinct animals, known in this country under the name 

 of Dudley fossils, having the body composed of three 

 transverse parts, and divided longitudinally by two deep 

 impressions, forming three elevated lobes. The anterior 

 part of the body is generally more or less semicir- 

 cular or lunate, having on the upper side two large 

 and generally reticulated eyes, shaped like kidneys. 

 This part is succeeded by numerous (from six to 

 twenty-four) transverse segments, and the body is 

 terminated by a large semicirclar plate less distinctly 

 articulated than the preceding part. Some account 

 of these remnants of animals are given in the article 

 FOSSIL REMAINS. No organs of locomotion or an- 

 tennae have been observed, and it appears to have 

 been the habit of these animals to roll themselves up 

 into a ball by bending the extremity of the body 

 beneath the breast, and bringing it into contact with 

 the head. Much diversity of opinion has been enter- 

 tained amongst naturalists as to the relations in nature 

 of these curious creatures. According to M. Alex- 

 andre Brongniart, who published a good monograph 

 of them, they are most analogous to the Limuli 

 and other entomostracous Crustacea, provided with a 

 great number of legs, of a more or less membranous 

 construction, and which, it may be readily conceived, 

 would have been entirely destroyed during the great 

 overthrow which has reduced these creatures to their 

 present state. This opinion has been strenuously 

 maintained by Audouin. It is, however, opposed by 

 Latreille, who observes that, supposing these animals 

 to have been destitute of legs, they would naturally 

 approach the Oscabrions (or Gasteropodous Chitons) ; 

 or rather, that they constituted the primitive type of 

 annulose animals, uniting on one side the last 

 mentioned molluscous creatures with the entomos- 

 tracous Crustacea, as well as with the genus Glomeris 

 (amongst the myriapodous insects) ; adding, that no 

 branchiopodous Entomostraca has hitherto been dis- 

 covered capable of contracting itself into a ball, which 

 peculiarity is only observed in the crustaceous genera 

 Typhis, Sphceroma, Tylos, and Armadillo (see a figure 

 of the last-named genus in the article CHILOGNATHA), 

 and in the apterous genus Glomeris (also figured in 

 the last named article) ; between which tribes there is 

 a considerable hiatus. The genera Calymene and 

 Asaphus, amongst the Trilobites, on account of their 

 contractility, evidently approach the Glomeris and 

 some of the isopodous Crustacea (Sphceroma} ; but 

 the Trilobites have the terminal segment of the body 

 entire, and not furnished with lateral swimmerets as 

 in the SpluEromae ; but the same negative character 

 exists in the Glomeris,and especially in the genus Tylos, 

 of which the upper side of the thoracic segments is 

 divided into three lobes. The discovery of the genus 

 Serolis on the coasts of Patagonia, has afforded an- 

 other proof of the correctness of Latreille's idea of the 

 oscillant situation of these creatures between the 



Isopoda and the myrapodous insects, the eyes in that 

 genus being situated in the same vertical situation, 

 and of the same lunate form, as in the Trilobites. 



a Asaphus expansus. b The same rolled up. 



Moreover, the body is longitudinally divided into three 

 lobes like the Trilobites. The legs and caudal swim- 

 merets scarcely extend beyond the sides of the body ; 

 but the antennae are very large and distinct. This 

 genus has lately been described and figured in detail 

 in the Transactions of the Albany Institute, by Mr. 

 James Eights, under the name of Brongniartia. Much 

 of this diversity of opinion has resulted from the very 

 much worn state of the Trilobites, v4iich have, in 

 many instances, been so rubbed, that their eyes have 

 been entirely effaced ; but it is questionable whether 

 any Trilobite was ever destitute of those organs which 

 Dr. Buckland has, in his Bridgewater Treatise, de- 

 scribed at great detail in connexion with their fitness 

 for the situations in which the animals are supposed 

 to have resided. Mr. J. V. Thompson, in the last 

 of his Zoological Researches, has adopted the opinion 

 of M. Audouin, considering that the eyed Trilobitcs, 

 Calymena, and Asaphus, are most approximate to 

 those phyllopodous Crustacea of which Apus is the 

 type, and that the genera Bucephalithus, Oygia, and 

 Paradoxides, are analogous to such phyllopodous 

 genera as Branchypus, Eulimena, and Cheirocephalus. 



The works of Brongniart above referred to, and 

 that of J. ,W. Dalmad (Ueber die Palaeaden oder die 

 sogenannten Trilobiter. Nurnberg, 1828), and the 

 works therein referred to, must be consulted for the 

 determination of the generic and specific characters 

 of these perplexing and singular animals. 



TRIMERA (Latreille). A primary section of the 

 coleopterous insects, having apparently only three 

 joints in all the tarsi ; but in effect having four, the 

 third being very minute and buried between the lobes 

 of the second joint. Latreille introduces into this 

 section the families: 1. Fungicoles (typical genera 

 Eumorphus and Endochymus, Fabricius) ; 2. Aphidi- 

 phagcs (Coccinclla) ; and 3. Pselaphiens (Pselap/nts). 

 The relations of these three groups seem in nowise 

 to warrant this association ; the Fungicoles appear 

 most nearly allied to some of the fungivorous Ne- 

 crophaga, notwithstanding the diversity in the number 

 of the joints of the tarsi, and the Pselaphidce are even 

 more closely allied to the Staphylinidce. The Cocci- 

 ndlidce, on account of their peculiar characters, and 

 the insectivorous habits of the larvae, are a very 

 distinct group ; but, perhaps ought not to be raised 

 beyond the rank of a family, instead of constituting a 

 section by themselves. 



TRING A. A genus of stilt or running birds, 

 frequenting the margins of the waters, but rarely, if 

 ever, wading ; and seeking their food on the oozy 

 banks rather than the sandy and pebbly shores. 



