BRITISH TUNIC'ATA. 



Family 7. BOTRYLLIDA:. 



Individuals [short], with the thorax and abdomen 

 united ; arranged in distinct circular or elongated 

 systems around a common cloaca! orifice, and enveloped 

 in a sessile inc rusting mass ; the viscera at the side of 

 the branchial sac. 



[The colony is incrusting, usually thin but some- 

 times thick and fleshy ; the systems are circular, ellip- 

 tical, or branching; the test is usually soft; the 

 branchial sac is large and well developed ; the dorsal 

 lamina is plain ; the tentacles are simple and do not 

 exceed sixteen in number.] 



FIG. 114. Structure of Botryllidte. Botrylloides rosaceus (Sav.) M. 

 Edw. (Savigny, pi. xx, ff. 3-', 3 :! .) a. An individual seen from the 

 right side ; the tunic supposed to be transparent and the branchial 

 sac visible. l>. Another individual seen from the left side. B, 

 branchial aperture ; C, atrial aperture ; c, stomach ; F, branchial 

 sac ; g, intestinal loop ; H, anal aperture ; K, ovary. 



Genus 22. BOTRYLLUS Gaertner, 1774. 



Boh-i/llm GAERTNER in Pallas' Spicil. Zool. I, fasc. 10 

 [(1774), p. 35] ; LAMAECK [in Mem. du Mus. I (1815), 

 p. 835; [pars] Hist. nat. Anim. s. Vert. [Ill (1816), 

 p. 106, and] ed. 2, III [1840], p. 505; SAVIGNY Mem. 

 Anim. sans Vert. pt. 2 [1816], p. 197; CUVIER Regne 

 Anim. [II (1817), p. 499; LAMOUROUX (pars) Exp. metli. 

 Polyp. (1 (S '-1), P- 76;] BLAINVILLE Man. Malac. et Conch. 



