TUNICATA. 5 



Branchial Sac with four large folds on each side, separated by wide interspaces 

 (Plate I., fig. 5). There are about six strong bars on a fold and five in the area 

 between two folds. The bars (fig. 6, i. I. b.) are wide and ribbon-like, and are far 

 apart (except on the folds). The transverse vessels are of at least three different sizes, 

 arranged symmetrically (Plate I., fig. 6). The meshes are elongated and may contain 

 as many as twenty-five to thirty stigmata. The wall of the branchial sac is thrown 

 into occasional undulations, as shown in fig. 6. 



Tentacles large (15 mm. x 2 mm.), simple, about thirty in number; a few are 

 smaller, but there is no regular alternation. 



Dorsal Lamina a plain membrane, short and not very wide. 



Dorsal Tubercle large and complicated in form (Plate I., fig. 7), having broken up 

 into several distinct spirals with the horns coiled inwards. 



Alimentary Canal very large, on the left side, cesophageal opening very far 

 forward, within 5 cm. of the anterior end of the body, and leading by a short funnel- 

 shaped oesophagus to a large smooth-walled stomach (Plate I., fig. 8, St.). The 

 intestine is short and wide, and has the usual course (see fig. 8). The wide anus, 

 close to the oesophagus, is fringed with about ten simple or compound projections. 



Gonads enormous and placed on both sides of the body. They are like yellow 

 sausages, fully 1 cm. in diameter, with small nipple-like ducts at their atrial ends 

 (fig. 8, (].}. Numerous large and small irregularly shaped endocarps (figs. 8 and 9) are 

 present on both sides of the body ; they measure up to 2 ' 5 cm. in length. 



This very fine species is probably the largest Styela known. In some respects it 

 recalls Styela rustica of Arctic seas, but is very much larger, and differs in details of 



PIG. I. Styela spectabilis, FIG. 2. Styela spectabilis, 



from left side. from right side. 



(About one-third natural size.) (About one-third natural size.) 



structure. Although the two apertures differ so greatly in appearance (Plate 1., 

 figs. 2 and 3) in the preserved specimen, they are probably both widely open and more 



K 2 



