-popular SKrtianarj) of STm'matrtr Mature. 717 



vith the microscope. Whilst engaged in 

 this investigation, Dr. Kirtland, of Portland, 

 Ohio, informed Mr. Lea of his ability to dis- 

 tinguish the female and male shells of the 

 same species, without having recourse to the 

 included animal ; and he says that a very 

 short series of examination satisfied him 

 fully as to the establishment of the difference 

 of sexes. The female, sustaining her very 

 large burthen, naturally requires, he observes, 

 more space within the valves ; hence an en- 

 largement of the posterior portion of the 

 shell is generally found, differing in its form 

 in various species. 



It seems to be a matter of doubt, according 

 to Mr. Lea, on what these animals subsist, 

 but he had strong reasons for believing thet 

 they feed on animalcules which are ever 

 found to exist in water, and which they 

 might separate from the constant stream 

 which they pass from the posterior part of 

 the shell, and which must be taken in at 

 another part. This operation he witnessed 

 frequently in a vessel in which he kept the 

 Xaiiulce tor some months. If the water was 

 not changed for twenty-four hours, he uni- 

 flrmly found the animals quiet, but within 

 a few minutes after it was changed they as 

 uniformly commenced the passage of this 

 constant streiim, which he considers to be 

 the result of the action of the separation of 

 the animalcules from the water. Referring 

 to the fact of pearls being found in other 

 freshwater bivalves, Mr. Broderip observes 

 that the brilliant and variously-coloured 

 nacre with which many of the species are 

 lined, and the extreme thickness of some of 

 the shells, are very remarkable. That pearls 

 should be found in them will not surprise 

 those whose attention has been drawn to 

 their internal surface. Pennant remarks 

 that 3///a Margaritifera of Linnaeus ( Unio 

 elonyaliis) is noted for producing quantities 

 of pearls, and formerly there were regular 

 fisheries in many of our rivers to obtain 

 them. As many as sixteen have been taken 

 from one shell. The Esk and the Conway 

 were famous in this way. The latter river, 

 in the days of Camdcn, was noted for them.. 

 Sir Richard Wynn, of Gwidir, chamberlain 

 to Catherine, queen to Charles II., is said to 

 have presented her Majesty with a Conway 

 pearl which is to this day honoured with a 

 place in the regal crown. Pennant, who 

 states this, adds, that the shells are called 

 by the Welsh, Crigen Dilune, or Deluge 

 Shells, as if left there by the deluge. The 

 river Irt, in Cumberland, also produced them ; 

 and Sir John Hawkins, the circumnavigator 

 [as mentioned in the article MYA], hod , 

 patent for fishing that river. Britain, indeed, 

 had early acquired a reputation for its 

 pearls ; for, according to Suetonius, they 

 were Caesar's inducement for undertaking 

 his British expedition. This, however, does 

 not seem very probable. Pliny, indeed, 

 speaks of the pearls of our island as small 

 and ill-coloured, and refers to the breastplate 

 which Crosar himself had brought home and 

 dedicated to Venus Genetrix in her temple, 

 adding that he wished it to be understood 

 that the offering was formed of British 

 pearls." 



I UNIPELTATA. A family of Crustacea, 

 ! belonging to the order Stmnapoda, and com- 

 prising one genus only, Squilla [which see]. 



UNOGATA. The name given by Fabri- 

 cius to a part of the Arachnida, order 1'ul- 

 monario, and comprehending the Scorpions 

 [wliich see]. 



UPHOLSTERER BEE. (Osmia papa- 

 verif.) This name is given to a species of 

 wild bee, found in France, belonging to the 

 genus Osmia, These ingenious artificers 

 excavate holes in the earth for the recep- 

 tion of their young, and line ihcm with on 

 elegant coating of flowers or leaves ; an 

 operation wliich is so pleasingly described 

 in Messrs. Kirby and Spence's Introduction 

 to Entomology, that we beg to transfer the 

 account they give of it, from their pages 

 to our own. "This little bee, as though 

 fascinated with the colour most attractive 

 to our eyes, invariably chooses for the hang- 

 ings of her apartments the most brilliant 

 scarlet, selecting for its material the petals 

 of the wild poppy, which she dexterously 

 cuts into the proper form. Her first process 

 is to excavate in some pathway a burrow, 

 cylindrical at the entrance, but swelled 

 out below to the depth of about three 

 inches. Having polished the walls of this 

 little apartment, she next flies to a neigh- 

 bouring field, cuts out oval portions of the 

 flowers of poppies, seizes them between her 

 legs, nod returns with them to her cell ; 

 and though separated from the wrinkled 

 petal of a half-expanded flower, she knows 

 how to straighten their folds, and, if too 

 large, to fit them for her purpose by cutting 

 off the superfluous parts. Beginning at the 

 bottom, she overlays the walls of her man- 

 sion with this brilliant tapestry, extending 

 it also on the surface of the ground round 

 the margin of the orifice. The bottom is 

 rendered warm by three or four coats, and 

 the sides have never less than two. The 

 little Upholsterer, having completed the 

 hangings of her apartment, next fills it with 

 pollen and honey to the height of about half 

 an inch ; then, after committing an egg to 

 it, she wraps over the poppy lining so that 

 even the roof may be of this material, and 

 lastly closes its mouth with a small hillock 

 of earth. The great depth of the cell com- 

 pared with the space which the single egg 

 and the accompanying food deposited in it 

 occupy, deserves particular notice. This is 

 not more than half an inch at the bottom, 

 the remaining two inches and a half being 

 subsequently filled with earth." 



UPUPA. [See HOOPOK.] 



URAN-UTAN. [See ORABTO.] 

 UR AlH IID^. A family of Lepidopterous 

 insects, belonging to the HETEROCERA ; com- 

 prising several very anomalous exotic ge- 

 nera, which, from their apparently occupy- 

 ing a station between the Ilesperiae and 

 Sphinges', Latreille named Hesperi-Sphinges. 

 Since the discovery of its preparatory states, 

 however, it is allowed to belong to the 

 Heterocerous section of the oitler. Mr. 

 Westwood tells us, that "the splendid 



