350 PROCEEDINGS:^: BOSTON SOCIETY NATURAL HISTORY. 
confusion the writer has adopted the expedient of placing the old 
name after the new one in brackets, as proposed by Michaelsen and 
already employed by other writers also, thus: Holozoa [Distaplia] 
clavata (Sars). 
Abbreviations used in Illustrations. 
at — atrial orifice. Iv — larva. 
bp — brood pouch. mb — muscle band. 
br — branchial orifice. tnp — muscular process. 
dig — dorsal languet. <xl — oviduct. 
en — endostyle. oe — esophagus. 
fp — fecal pellet. ov — ovary. 
g — ganglion. r — ^ rectum. 
gc — gastric caecum. rep — reproductive glands. 
i — intestine. s — stomach. 
ilv — internal longitudinal vessel. sel — sperm duct. 
ing — intestinal gland. t — testis. 
Ig — atrial languet. vp — vascular process. 
The illustrations are from drawings and photographs by the author. 
Family BOTRYLLIDAE Verrill, 1871. 
Genus Botryllus Gaertner and Pallas, 1774. 
Systems simple, circular or elliptical, composed of comparatively 
few zooids. Colony thin and incrusting in the typical species. 
Botryllus schlosseri (Pallas). 
Text-fig. 1; PI. 39, fig. 10. 
1766. Alcgnnium Schlosseri Pallas, Elench. Zoophyt.. no. 208. 
1816. Botryllus Schlosseri Savigny, Memoires sur les animaiLx sans vertebres, 
pt. 2, p. 200, pi. 20, fig. 5. 
1838. Botriillus stellatus Couthouy, Boston Journ. Nat. Hist., vol. 2, p. 111. 
1841. Botri/llus stellatus Gould, Report on Invertebrata of Massachusetts, 
ed. 1, p. 320. 
1870. Botryllus Schlosseri Binney, Gould's Invertebrata of Massachusetts, 
ed.2, p. 3, pi. 23, fig. 319. 
1870. Botryllus Schlosseri Dall, Proc. Boston Soc. Nat. Hist., vol. 8, p. 255. 
1871. Botryllus Gouldii Verrill, Amer. Journ. Sci., ser. 3, vol. 1, pp. 211, 212, 
fig. 14-19. 
1872. Botryllus Gouldii Verrill, Amer. Journ. Sci., ser. 3, vol. 3, p. 213. 
