148 University of California Publications in Zoology. [Vol.6 



grown, become separate from each other and constitute the 

 sexual generation (fig. 2), each individual producing one of the 

 "solitary" type which, in turn, propagates by budding, and so on. 

 Individuals of the bud-producing generation of this species 

 are nearly cylindrical and both orifices are terminal. The length 



Fig. 2. — S. fusiformis runcinata — sexual or aggregate generation. 



of the largest specimens is 70-90 mm. The test is thin and soft 

 anteriorly but thick and firm posteriorly, especially on the ventral 

 side of the posterior third, where it forms a thick, firm gelatinous 

 mass. The heart is on the ventral side, immediately in front of 

 the intestinal tract called the "nucleus." A chain of buds 

 encircles this nucleus and all but its most proximal portion is 

 embedded in the thick test. (Fig. 1, ch.) 



Fig. 3. — Young zooid of S. fusiformis runcinata taken from the chain: 

 hi., atrial orifice; br., branchial orifice; v., vascular canal. 



The individuals of the aggregate or sexual generation are 

 somewhat elliptical in outline with processes at each end. The 

 processes are always asymmetrical at the outset. The branchial 

 orifice is inclined upward, while the atrial is directed nearly back- 

 ward. There are seven body muscles, the anterior four and 



