vou 2, pt. 2.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 15 



gill, the ciliated cells of the gill being continued into the esophagus 

 into which they constantly carry a stream of mucus and entangled 

 food particles. As in Pyrosoma, there is a line of cilia from the eso- 

 phageal aperture to the posterior end of the endostyle, where it is 

 continuous with the lateral ciliated bands of the endostyle. The 

 direction of the currents caused by these cilia is not known. (For 

 a drawing of this line of cilia in another species see figure 38, page 65.) 

 The narrow esophagus curves to the right, then to the left, and is 

 continued into the intestine. The curve of the gut is therefore a 

 left-hand curve as in the Ascidians. The first portion of the intestine 

 is somewhat enlarged, and might possibly be called the stomach, but 

 in reality there is no demarcated stomach. The intestine is straight. 

 It stretches along the dorsal side of the whole length of the gill, the 

 anal opening leading into the atrium, just back of the ganglion. At 

 the place where the esophagus joins the intestine two caeca arise. 

 These turn backward, lying one on each side of the mid line. The 

 position of the anal aperture in this species, far forward in the body, 

 should not be seriously disadvantageous, for it is behind the gill, and 

 there should be little danger of clogging the cilia currents of the gill 

 with the fecal wastes. 



The heart lies on the mid -ventral line a short distance in front of 

 the esophageal aperture, between the fifth and sixth body muscles, 

 in connection with a slight evagination of the mid-ventral surface of 

 the mantle. 



The stolon arises in front of the heart, on the mid-ventral line, and 

 runs forward in the median plane. As shown by Brooks (1886), it 

 is at first a single series of buds lying each with its ventral surface 

 toward the free tip of the stolon. Later the alternate links of this 

 chain become crowded out to opposite sides of the stolon, forming a 

 pseudobiserial chain of buds. At the tip of the stolon, whorls of from 

 5 1 to 15 2 individuals are formed. None of our specimens show more 

 than two whorls, one fully formed, the other beginning to assume the 

 radial arrangement. 



Opposite the intermediate muscles and near the median line are 

 two languet-like protuberances of the mantle (v. L, fig. 1), one on each 

 side, extending into the test and nearly to its outer surface. Streiff 

 (1908) has shown these in his figures. They are present also in 

 Gyclosalpa bakeri. They suggest comparison with the more numerous 

 and more developed mantle protuberances in Thalia and Travstedtia. 



The spheroidal ganglion and nerves need no description here. Above 

 the ganglion, and resting upon it, is a horseshoe-shaped eye with the 



1 Sigl, 1912, a and b 2 Our specimens from Naples. 



2621— Bull. 100, vol. 2—19 2 



