334 W. G. Van Name — Bermuda Ascidians. 



Clavelina (Stereoclavella) oblonga Herdman. 



Clavelina oblonga Hei-dnian, Prelim. Eep. Proc. Roy. Soc. Edin., 1879-80, p. 



724. 

 Clavelina oblonga Herdman, Report Voy. Challenger, Zool., vol. vi, pt. xvii. 



p. 246, plate xxxv, figs. 6-10. 

 Stereoclavella oblonga Herdman, Trans. Biol. Soc. Liverpool, vol. v, pp. 160- 



161, also Jour. Linn. Soc. Zool., vol. xxiii, p. 608. 



Plate XLVI. Figure 1. Plate XLVII. Figure 7. 



Plate LXII. Figure 130a. 



Individual animals club-shaped, the anterior end rounded, the 

 body tapering gradually into the very short stalk. The colony con- 

 sists of a number of such individuals quite closely grouped together, 

 united by the expanded bases of the stalks. 



The total length of the largest individuals (including the short 

 stalk) is about 30 mm . Removed from the test the zooid ordinarily 

 measures less than half this length, but large ones fully expanded 

 measure about 20 mm in length. 



The test is thick but perfectly transparent and colorless ; the 

 lower part may be slightly incrusted with fine sand. It is gelatinous 

 in consistency, firmer near the base. The zooids themselves are 

 nearly colorless. The stomach and intestine in life are brownish. 

 There are often spots of very pure opaque white on the thorax, and 

 always about the edges of the orifices. 



The musculature of the mantle consists of a rather small number 

 of slender bands, most distinct on the thorax. Beneath there are 

 very delicate transverse muscles placed close together. These form 

 an almost continuous but very thin layer about the thorax, but the 

 longitudinal muscles are much the stronger and the animals contract 

 greatly in length in preservation. The thorax contracts more than 

 the abdomen. In life when the animal is expanded the branchial 

 sac is fully half the length of the bod}'. 



There are 15 or more rows of stigmata, and sometimes 50 in a row. 

 The stigmata begin close beside the dorsal lamina. 



According to Herdman, the dorsal languets are short, conical and 

 tentacular, and separated by about their own length. The tentacles 

 are short and stout, about 20 in number, of two sizes placed alter- 

 nately. The dorsal tubercle is small and irregularly oval. 



In all the specimens obtained the reproductive organs were small, 

 but a large number of embryos in various stages were contained in 

 the atrial cavities of some of the zooids. 



