. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 64 ANNALS OF THE SOUTH AFRICAN MUSEUM Description Ascidia canaliculata is closely allied to A. sydneiensis Stimpson, 1855. Both species were synonymized by Van Name (1921). They have in common large, grooved siphons with digitate lobes and a characteristic transverse musculature limited to the right side of the body (Fig. 32B). The musculature consists of two ribbons of parallel fibres, one ventral and one dorsal. These ribbons are linked by very thin fibres which become visible when stained (Fig. 32
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 64 ANNALS OF THE SOUTH AFRICAN MUSEUM Description Ascidia canaliculata is closely allied to A. sydneiensis Stimpson, 1855. Both species were synonymized by Van Name (1921). They have in common large, grooved siphons with digitate lobes and a characteristic transverse musculature limited to the right side of the body (Fig. 32B). The musculature consists of two ribbons of parallel fibres, one ventral and one dorsal. These ribbons are linked by very thin fibres which become visible when stained (Fig. 32B). The gut always has a bulbous widening of the posterior intestine filled with sediment (Fig. 32A) even in very young Fig. 32. Ascidia canaliculata. A. Left side of body. C. Dorsal tubercle. B. Muscles on the right side. Remarks and distribution The only distinguishing characteristic of the species is the structure of the dorsal tubercle (Fig. 32C). In all the Atlantic, South African and Mozambican populations this has the shape of a 'V that is open anteriorly and has horns curled interiorly. It is not regular in pattern but rather undulated (Fig. 32C). In A. sydneiensis, a Pacific Ocean species, the dorsal tubercle is pierced by several openings. Authors who have examined both species consider them distinct (Sluiter 1898a; Hartmeyer 1911), except for Millar (1955) who was doubtful. Ascidia sydneiensis is somewhat variable in the Pacific. Tokioka (1953) recognized three subspecies in Japan: A. sydneiensis sydneiensis, which has a. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original South African Museum. Cape Town : The Museum
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
