300 CEYLON PEARL OYSTER REPORT. 



Test thick and stiff, forming a more solid mass than is usual. 



Mantle delicate, with about ten slight longitudinal muscle-bands on each side. 



Branchial Sac with internal bars supported by wide triangular connecting ducts 

 (fig. 16). Meshes each contain two or three rather wide stigmata. 



Dorsal Lamina represented by a series of closely placed rather large triangular 

 languets (fig. 17). 



Tentacles rather long, eight larger and eight smaller. 



Dorsal Tubercle very small and simple. 



Locality : Coral Eeef, Galle, February 14, 1902 ; one specimen. 



Ecteinascidia sluiteri, n. sp. Plate I., figs. 9 to 14. 



External Appearance. A small transparent colony consisting of two individuals 

 and an empty test, and some buds attached to a slender creeping stolon (fig. 9). The 

 stolon is marked with constrictions or joints, and has some adhering sand (fig. 10). 

 The Ascidiozooid is oblong and erect, with both siphons at the anterior end, and 

 rapidly narrowing at the posterior end to the attachment with the stolon. The 

 apertures are not lobed, but have many slight creases. The Ascidiozooid measures 

 7 millims. in length by 3 '5 millims. in breadth at the atrial siphon. The stolon is 

 about 4 centims. in length. 



Test thin and colourless, allowing the branchial sac to be seen through. 



Mantle thin, and for the most part transparent. The muscles are arranged 

 in three longitudinal bands (one dorsal and two lateral) of short, transversely running 

 forked bundles. The dorsal band is interrupted in its posterior three-fourths by the 

 rectum (fig. 11). 



Branchial Sac large, and runs the whole length of the body. The transverse 

 vessels are narrow and all alike ; the internal bars are very narrow and the connecting 

 ducts are slight. The stigmata are long and regular, one or two to a mesh (fig. 12). 



Tentacles of two sizes, and there are about twenty in all. Those at the ventral 

 edge are the largest (fig. 13). A large number of Acinetan parasites are seen attached 

 to the tentacles and to the peripharyngeal band. 



Dorsal Lamina represented by a series of very small languets. There is very 

 little interruption of the stigmatic network on the dorsal edge. 



Dorsal Tubercle a small simple rounded opening (fig. 13). 



Alimentary Canal slender. The stomach has slight longitudinal folds and narrows 

 at the pyloric end, where the intestine is constricted (fig. 14). 



Locality : Station LVIIL, off north end of Karativo Island, 9 to 26 fathoms. 



The chief peculiarities of this species are the constricted stolon and the peculiar 

 short forked muscle bundles suggesting the condition seen in some species of Corella 

 (e.g., C. japonica), and the well-marked siphons which caused us to enter the animal 

 when dredged as an " Ascidia-like Clavelinid " in our field-notes. 



Omitting from consideration those species described as " Ecteinascidia," which have 



