ESSON1TK 



KTHKRIA. 



i'. Luriut, the True, or Freeh- Water Pike, Pickerel!, True Jack, or 

 Gedd, U a well-known fish, esteemed for it* food, and remarkable for 

 its Toracioua and destructive habits. It is the longest-lived ami 

 largest of fresh-water fishes, and many wonderful atories are narrated 

 of it Owner gives an account of one, the skeleton of which was 

 preserved at Mannheim, which weighed 350 Ibs., and waa probably 

 between 300 and 300 yean old. Pennant informs us of one 90 years 

 old; and pikes from SO to 70 Ibs. weight have been taken in 

 Scotland and Ireland. It grows with great rapidity, attaining a length 

 of from 8 to 10 inches in its first year. The Mannheim pike was 

 said to hare been 19 feet in length, and in our own country they 

 hare been taken 9 feet long. The Pike eaU up everything eatable 

 which comes in its way. Being strong, swift, and courageous, it 

 masters all other fishes in its locality. U will also attack birds and 

 small quadrupeds, if within reach, and has been known to quarrel 

 with the otter for its prey, and to assault man himself. Pikes are 

 found in Europe, Asia, and North America. In the United States 

 there are several species of Ktos. 



The habits of the Sea-Pike, or Oar-Fish (Bclone rulyari*), and the 

 Saury (Scombtntox) are not so well known. They are gregarious, and 

 swim near the surface of the water, leaping out of it with great agility, 

 and playing round bodies which float on the surface of the sea. The 

 | 'iMiliar formation of the heads of these fishes renders the nature of 

 the food a subject of curiosity among naturalists ; but the question 

 is not yet settled. On the southern coasts of England and Ireland 

 they are common. The bones of the Belont are green : the flesh is 

 firm and white, and has much the flavour of that of the mackerel. 

 I BELONE ; SCOMBKRESOX.] 



ESSONITE. [GARNET.] 



ESTRILDA, a genus of Birds belonging to the Pauerina. The 

 species are known by the name of Waxbilla, They inhabit the Indian 

 Archipelago and Australia. 



KT.K'HIO is a kind of fruit consisting of achenia, or small closed- 

 up seed-like seed-vessels, placed upon a succulent receptacle. The 

 strawberry and the raspberry are of this nature, and are very 

 incorrectly called Berries, in the botanical sense of the word berry. 

 [FBI-IT.] 



ETHE'RIA, Lamarck's name for a genus of Concbjferous Molliuca, 

 placed by many authors among the C'/mmi</<r, but separated by Deshayes 

 and others. [CHAMACEA.] 



Animal closely approximating to that of L'nio. Lobes of the mantle 

 disunited throughout their length, and consequently without either 

 tubes or syphons. Below the foot the branchial of the right side 

 unite themselves to those of the left side in the medial line, and 

 leave below them a rather large canal, in which the vent terminates. 

 The branchial leaflets are unequal, strongly striated and festooned 

 on their free border. The mouth is rather large, and furnished on 

 each side with a pair of palps like those of the Uniona. Finally 

 (and, as Deshayes observes, it is a great singularity in an animal 

 that lives attached to foreign substances), it is provided with a very 

 large foot, which may be compared in regard of its form and position 

 with that of I'nio. 



Shell adherent, thick, nacreous, very irregular, inequivalve, inequi- 

 lateral ; umbones short, thick, indistinct ; hinge toothles, irregular, 

 undulated, callous ; ligament longitudinal, tortuous, external, pene- 

 trating pointedly into the interior of the shell ; muscular impressions 

 oval, irregular, one superior and posterior, the other inferior and 

 anterior ; pallia! impression narrow and small. 



M. Deshayea observes that on examining the shells of this genus, 

 in which the ligament is not ruptured, it appears that the ligament is 

 not entirely internal or subinternal, like that of the oysters, but 

 that it has completely the structure of external ligaments. It is 

 when the shells are young that the structure of the ligament is most 

 easily recognised. There are two muscular impressions, always very 

 distinct in old individuals ; but in the young ones it sometimes happens 

 that one only can be distinguished, and it was upon an individual in 

 this state of growth that M. de FeYugnac established his genus Mullrria, 

 which, in the opinion of M. Deshayes, cannot be retained. With regard 

 to the crcnulations on the hinge adverted to by M. de Fdrussac, 

 M. Deshayes states that he had seen on the very individual which 

 M. de Ftfrusaac had in his hands some small fractures resulting, as it 

 appeared to M. Deshayes, from this cause, namely, that the shell having 

 been taken with the animal, the valves bad been separated by attacking 

 the ligament with a sharp instrument. 



Lamarck considered the genus Ktheria to be marine, and accounted 

 for its having escaped the notice of zoologists because it was attached 

 to rocks at gnat depths in the sea. Mr. O. R Sowerby, after noticing 

 the locality attributed to the genus by Lamarck, remarks that two 

 circumstances observable in the Kthtria (E. temilunata), figured in 

 his plate, would have induced him to suspect that this was a fresh- 

 water shell, or at least an inhabitant of actuaries at the mouths of 

 rivers; 1st, its having an epidermis, which remains only in those 

 parts least exposed to the action of the water, the greater part 

 especially of the upper valve being eroded in a very irregular manner ; 

 and 2ndly, its being partly covered with the remains of those ovate 

 vesicular bodies, supposed to be the eggs of some molluscous animals 

 so frequently seen on fresh-water shells. M. Cailliaud was the first 

 to make known the fact that the genus U an inhabitant of the fresh- 



waters, and M. de Frfrussac (' MiSmoires de la SocieV d'HUtoire 

 Naturellu', vol. i.) published a paper on the subject from M. C'ailliaud'* 

 materials, iu which the former also made a revision of the species. 

 M. Deshayes, in his treatise on the genus (' Encyclop&lie Mdthodique'), 

 states that individuals of the same species adhere by the one or the 

 other valve indifferently, which, he remarks, is not the case with the 

 Oysters or the Chanue. That El/aria may be attached indifferently 

 by either valve there is DO reason to doubt after the assertion of 

 M. Deshayes ; but Mr. Broderip (' Zool. Trans.,' vol. i.) observes that 

 the same species of Cliama is sometimes attached by the right, some- 

 times by the left valve. [CHAMACEA.] M. Rang, during a voyage 

 to Senegal, made some interesting observations on Ethrria which 

 live two hundred leagues from the mouth of the river iu the 

 Senegal, and, together with M. Cailliaud, who received the animal 

 from the Nile, published a memoir (' M<Smoires du Muslum d'HUtoire 

 N.itmvlle') full of interest, in which the animal was described for the 

 first time. The rivers of Africa and Madagascar appear to have 

 afforded the specimens (which are still rather scarce in cabinets) 

 hitherto collected. M. de rYrussac, iu his memoirs, gives the following 

 information from M. Cailliaud . *' We first meet with Ethcria," says 

 that zealous traveller, " after passing the first cataract ; and they do 

 not appear to exist below; they become very abnudant in the province 

 of Rebata, beyond the peninsula of Meroe. The inhabitants mil. -a 

 them on the banks of the river to ornament their tombs with them, 

 and they say that they come from the more elevated parU of the 

 Nile, from Simla, where they are eaten." M. Cailliaud found them as 

 far as Fazoql, the most distant country into which he penetrated 

 from the Blue River. In Seuuaar the inhabitants informed M. ( ailliaiid, 

 that during the summer season, when the river was low, they took 

 them with the animal ; but notwithstanding all his endeavours 

 M. Cailliaud could not obtain any living specimens, the river being 

 then always to high. They ore said to be very common in the 

 Jaboussi, a river which runs into the Blue Nile, and in all appearance 

 the numerous confluent streams of this great arm of the Nile produce 

 them also. The number found upon the tombs throughout Ethiopia 

 is so great, that it is astonishing that Bruce and Burukhardt should 

 not have mentioned them. ('ZooL Journ.,' vol. i.) 



i miiuntittt. 



Lamarck recorded four species of Klheria, which he divided into 

 two sections, each containing two species. The first of these consists 

 of species which have an oblong callosity in the base of the shell ; the 

 second, of those which have no encrusted callosity at the base of the 

 shell. These four species M. de Fcrussac (with justice, in the opinion of 

 M. Deshayes) reduces to two ; so that the sections, as left by Lamarck, 

 would each, in that case, consist but of one species, namely, the first 



of /;. tllij.Hra, and the n ml of /.'. sn,nlun,n,i. M. Deshayes remarks 



that Lamarck saw but a very small number of individuals, and not being 

 aware of the! r extreme variation, established species from the form of the 

 shell ; and it is certain, he adds, that if we were to follow the same indica- 



