ARTOTROGUS. 



[ 



] 



ASCIBICOLA. 



Horticult. Sac. i. p. 3, pi. 4. figs. 27-29 ; 

 Crypt Bot. p. 247 ; De Bary and Wciroiiin, 

 Beit. iv. 



ARTOTRO'GUS, Boeck.— A genus of 

 Entomostraca, Ord. Copepoda. Four Brilisli 

 species; marine, living in the brancliial sacs 

 of Ascidice, or on the integument of marine 

 Invertebrata. 



BiBL. Bradv, Copepoda {Ray Sac.'), iii. 

 p. 59. 



A'RUM, L. — A genus of Aracese (Flow. 

 PLmts). Anmi maoilatum, the common 

 Cuclvoo-pint, has a tuberous rhizome in 

 which is produced much starcli. This starcli 

 is extracted in the same way as Arrow-root 

 starch is from the rhizomes of Marantacefe 

 &c.,and is called Portland Arrow-root (PI. 

 40. lig. 11). See Staech. 



AS'CARTS.— A genus of Entozoa, of the 

 order Coelelmintha and famil_y Nematoidea. 



Char. Body cylindrical, narrowed at each 

 end ; head furnished with three tubercles or 

 Aalves : mouth terminal, situated between 

 the three tubercles ; male with one or two 

 spicula. 



The species are very numerous, occurring 

 in all the classes of theVertebrata and doubt- 

 fully in Insects. They are most commonly 

 found in the alimentary canal. We shall 

 only notice the species met with in man. 



A. Imnhricoides. The common round 

 worm. Inhabits the human small intes- 

 tine ; sometimes found also in that of the 

 ass, wild-boar, pig, and ox. "\'aries in length 

 from 3 to 15" ; is of a whitish colour ; the 

 head distinct, with the three valves (PI. 21. 

 fig. 9) finely denticulated on their inner 

 border, and each furnished near the summit 

 with a slightly projecting papilla. Female 

 larger and more common than the male. 

 Spicida two, equal. 



The recent ova are surrounded by an al- 

 buminous layer, the surface being studded 

 with numerous projecting tubercles. 



A. vermiadaris {0.vyi(ris verm.). The 

 human thread-worm. Found usually in the 

 rectum. White ; head frequently appearing 

 winged, or exhibiting two lateral vesicular 

 expansions (PI. 21. fig. 8 a), produced by 

 endosmosis. Mouth round when contracted, 

 exhibiting the three lobes when expanded. 

 CEsophagxis (e) containing a triquetrous 

 canal, and separated by a constriction from 

 the spherical stomach (d). Length, female 

 8 to 4-10 of an inch ; male shorter, with 

 the tail spirally coiled, much more rarelv 

 met with. Anus (cf) about 1-8 from the end 

 of the body ; spicidum single, with an ap- 



pendage. Uterus consisting of two lobes 

 (/() (ovaries); ovidnct (k) opening externally 

 near the middle of the body. 



A. mystax {cilata, Bell), 2 to 3 inches long, 

 as broad as a crow-quill ; common in the 

 cat, occasional in the human body. 



A. niyrovenosa, with the intestine black, 

 is found in the lungs of the frog and toad ; 

 and parthenogenesis is supposed to occur. 

 The females live in the lungs. The young 

 pass into damp earth or mud, where they 

 grow into sexual forms also producing em- 

 bryos, which do not arrive at sexual matu- 

 rity until they reach the lungs. No males 

 are fomid in the lungs. 



BiBi.. Dujardin, Hehninthes ; Leuckart, 

 Menscli. Parasit. ii. p. 153 ; Downe, Mn. 

 Mic. Jn. 1871 ,T. p. 55 {A. lumbr.) : Cobbold, 

 Entozoa, 1879, p. 243 ; Duj. Helm. p. 178 ; 

 Leuckart, Paras., 1879, p. 128. 



ASCHEMONEL 'L A, Brady.— One of the 

 branching Arenaceous Eoraminifera. The 

 chambers inflated, with 2 or more tubulated 

 apertures, any of which may produce a new 

 chamber. 



BiBL. H. B. Brady, Qu. Jn. Mic. 1879, 

 xix. p. 44. 



ASCIDIA, B.ist.— A genus of Tunicate 

 Mollusca, of the family Ascidiadse. 



Several British species. See Ascidiad^, 



ASCIDTADJi.— A family of Tunicate 

 Mollusca. 



Distinguished by their being single, 

 usually fixed (to foreign bodies, as sea- 

 weeds, shells, &c.), and the attachment of 

 the mantle to the test at the orifices only. 



Irregularly shaped, from half to several 

 inches long, often incrusted with stones and 

 shells, &c. ; with two orifices, one branchial 

 and pharyngeal, the other anal. British 

 genera : 



Ascidia, Bast. Test leathery ; branchial 

 orifice eight-lobed, anal six-lobed, both cir- 

 cular ; branchial sac not plaited. 



Molyula, Forbes. Globose, attached or 

 free ; test membranous, usually covered with 

 foreign matters ; branchial orifice six-lobed, 

 anal four-lobed, both on contractile naked 

 tubes. 



Cynthia, Sav. Sessile ; test leathery ; 

 branchial sac plaited longitudinally ; both 

 orifices four-sided. ' 



BiBL. Forbes and Hanley, Brit. Moll. i. 

 p. 29 ; Gosse, Mar. Zool. ii. p. 35 ; Pascoe, 

 Zool. 1880, p. 171. 



ASCIDIC'OLA, ThoreU.— A genus of 

 Entomostraca, Ord. Copepoda. 1 species, 

 marine. 



