. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. DESCRIPTION OF SPECIES i3S Tentacles. There are twenty-two tentacles in one specimen examined. They have short branches and are at most bi-pinnate. Dorsal tubercle. The dorsal tubercle in each of four animals has a narrow longitudinal slit-like opening, either straight, slightly sinuous, or very slightly curved (Text-fig. 58 B). This is quite distinct from the C-shaped opening described by Arnback in the typical form of the species. Branchial sac. The number of branchial folds varies; in one ani
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. DESCRIPTION OF SPECIES i3S Tentacles. There are twenty-two tentacles in one specimen examined. They have short branches and are at most bi-pinnate. Dorsal tubercle. The dorsal tubercle in each of four animals has a narrow longitudinal slit-like opening, either straight, slightly sinuous, or very slightly curved (Text-fig. 58 B). This is quite distinct from the C-shaped opening described by Arnback in the typical form of the species. Branchial sac. The number of branchial folds varies; in one animal there are seven on each side and in another seven on the left and six on the right. There are six to fourteen longitudinal bars on the folds and either one bar or none, between folds. Gut. In general shape the gut conforms to Arnback's description and figure, but the upwards bend of the rectum is less acute, in the ' Discovery' specimens. an. Text-fig. 58. Molgula setigera Arnback f. georgiana (St. 474): A, specimen with test removed; B, dorsal tubercle; C, gonad with one sperm duct; D, part of gonad with three sperm ducts. Molgula setigera f. marioni (St. 1563): E, specimen with test removed; F, dorsal tubercle; G, gonad. Gonads. The form of the gonads (Text-fig. 58 C, D) is fairly constant, resembling that of the type specimens, but the gonoducts are variable. Usually the oviduct (od.) is moderately long, but in at least one specimen is quite short; it is always directed up towards the atrial siphon. The sperm ducts () vary in number and position. There may be from one to five short narrow sperm ducts near the base of the oviduct. Remarks. These specimens from South Georgia have certain slight but constant differences from Arnback's types of M. setigera, and I have hesitated whether to include them in that species or to regard them as a new species. The presence of bristles only on the siphons, and the existence of several sperm ducts are perhaps minor differences
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