BORRERA. 



BOTRYDINA. 



of ammonia, appearing more transparent and 

 the colours more brilliant, probably from 

 their being more highly refractive. They are 

 difficult also to preserve. Even when 

 mounted in Canada balsam, they deliquesce 

 after a time, and large crystals take their 

 place. 



BIBL. Fox Talbot, Phil. Trans. 1837; 

 Brewster, Optics, 1853. 



BORRERA, Ach. (Physcia, Schreber). 

 A genus of Parmeliacese (Gymnocarpous Li- 

 chens), some species of which, such as B. 

 ciliaris, tenella and furfuracea, are common 

 on trunks of trees or old palings. B. ciliaris 

 is an especially favourable lichen for obser- 

 ving the organs called spermagonia (See Li- 

 CHENES). The specimens which possess 

 these display them under the form of pro- 

 jecting brown or black tubercles upon the 

 narrowest lobes of the thallus, mostly above. 

 The largest size which they attain is about 

 1-25" in diameter. Examined as opake ob- 

 jects under a low power, they display pores 

 or irregular fissures above. Fine sections 

 examined under high powers as transparent 

 objects, show that the fissures or pores lead 

 into sinuous cavities lined by delicate fila- 

 ments (sterigmata) bearing at their sides 

 minute cylindrical corpuscles about 1-6000" 

 long (spermatia), which readily become de- 

 tached, and exhibit a molecular motion in 

 water. 



Hedwig first supposed these spermagonia 

 of Borrera ciliaris to be male organs, but the 

 idea was rejected until Itzigsohn pointed out 

 the existence of the spermatia and the mo- 

 lecular movement in the same species, which 

 he regarded as analogous to that of sperma- 

 tozoids. Tulasne has since elaborated the 

 whole question, and his statements will be 

 found under LICHENES. 



BIBL. Systematic : Hook. Br. Fl. ii. part 

 1. 226; Schjerer, Enumeratio, &c. p. 10, 11. 

 pi. 2. fig. 1 (as Physcia). Physiological : 

 Hedwig, Theoria Generationis, p. 120. pi. 30, 

 31; Itzigsohn, Botanische Zeitung, viii. 393. 

 913. ix. 153 ; Tulasne, Memoire sur les Li- 

 chens, 1852. 136. pi. 2. figs. 16, 17. (Ext. 

 Ann. des Sc. nat. 3 ser. xvii. p. 160. pi. 2. 

 figs. 16, 17.) 



BOSMINA, Baird. A genus of Eritomo- 

 straca, of the order Cladocera and family 

 Daphniadae. 



Char. Head terminated in front by a sharp 

 beak directed forwards, and from the end of 

 which project the long, many-jointed, curved 

 and cylindrical superior antennae ; inferior 

 antennas two-branched, one branch with 



three, the other with four joints ; five pairs 

 of legs. 



B. lonairostris (PI. 15. fig. 2). Superior 

 antennas with twenty joints. 



Found in the New River and Hampstead 

 ponds. (Nat. size, fig. 2 *.) 



BIBL. Baird, Brit. Entomostr. 



BOSTRYCHIA, Fries. See CYTISPORA. 

 Bostrychia, Montagne, is a Florideous Alga 

 =Alsidium, Agardh. 



BOTHRENCHYMA. Pitted tissue of 

 Plants. See TISSUE, Vegetable, and refer- 

 ences under that head. 



BOTHRIOCEPHALUS, Rudolphi. A 

 genus of Entozoa, of the order Sterelmintha 

 and family Cestoidea. 



Char. Body long, flat, soft and jointed ; 

 head slightly tumid, oval or somewhat qua- 

 drangular, with two opposite depressions, or 

 with four ear-like appendages, or with four 

 depressions furnished with hooks; genital 

 pores mesial. 



The species are common in fish and birds, 

 more rare in mammalia, and very rare in 

 reptiles. They usually inhabit the alimentary 

 canal, sometimes the abdominal cavity. 



Thirty-four species are enumerated by Ru- 

 dolphi, ten of which are doubtful. Dujardin 

 enumerates twenty-three species. 



Bothriocephalus latus (Tania lata, the 

 broad tape-worm) is the only species which 

 inhabits the human intestines. In it the 

 head is somewhat ovoid, with two elongated 

 opposite depressions, but no hooks; the 

 neck generally not distinct. The joints of 

 the body are very broad in proportion to 

 their length. The orifices leading to the 

 ovaries are situated in the centre of the flat 

 surface of each joint, and around them the 

 oviducts are seen, having a radiated or stel- 

 late appearance. Sometimes a minute body 

 can be seen projecting from the genital pore 

 the male organ. It exclusively inhabits 

 the small intestines. It is rare in England. 

 It is sometimes 20 feet in length. 



See T^ENIA and ENTOZOA. 



BIBL. Rudolphi, Entoz.Synops.; Bremser, 

 Ueber lebend. Wurmer, &c.; Dujardin, Hist. 

 Nat. d. Helminth. ; Eschricht, Anat. Phys. 

 Untersuch. ii. die Bothrio. ; Blanchard, Ann. 

 d. Sc. nat. 3 ser. xi. 



BOTRYCHIUM, Swartz. A genus of 

 Ophioglossaceous Ferns. Moon-wort (Bo- 

 trychium Lunaria) is an indigenous repre- 

 sentative. 



BOTRYDINA, Breb. A genus of Pal- 

 melleae (Confervoid Algae), consisting of one 

 species of green microscopic plants, B. vul- 



