6 DISCOVERY REPORTS 



The scheme of nomenclature followed in this paper is based on that described by Yount (1954) in which 

 the test is described in terms largely formulated by Stiasny (1926), while the muscle notation follows that 

 of Streiff (1908). 



SYNONYMY AND PREVIOUS DESCRIPTIONS 

 It is proposed in this section to describe only those works that are relevant to a discussion of the 

 synonymy of Salpa fusiforniis and its related species, and in particular to the status of the serrated 

 forms. For a detailed account of the taxonomy of the Salpidae in general, reference should be made 

 to Metcalf (1918) or to Thompson (1948), who deals with the pelagic Tunicata as a whole. 



It should be remembered that in the early nomenclature of the group, solitary and aggregate forms 

 of the same species often acquired different names. For example, Cuvier (1804) gives the name 

 S. fusiformis for the aggregate form of the species, while Chamisso (1819) calls the solitary form of 

 the same species S. runcinata. With the realization, largely as a result of the work of Chamisso (1819), 

 that the two forms were morphologically different stages in the life-history of a single species, the one 

 sexual, the other asexual, the two names became linked by a hyphen. Thus the species became known 

 as S. runcinata-fusiformis Chamisso-Cuvier (Krohn, 1846; Traustedt, 1885; Herdman, 1888). Sub- 

 sequently it was considered by Ritter (1905) that the first name in the couplet should be that having 

 priority and so the specific name became S. fusiformis -runcinata Cuvier-Chamisso. While many 

 authors followed the lead of Krohn (1846), others, notably Apstein (18946), foreshadowed modern 

 usage in dropping the second name of the couplet, so making the species S. fusiformis Cuvier. In the 

 following account of previous literature the nomenclature used is that of the author under discussion. 

 Herdman (1888) described from the Challenger collections the solitary form of a new species— 

 S. echinata — which differed from S. runcinata-fusiformis Cuv.-Cham. in having a serrated test and in 

 M. (body muscles) IV-IX being parallel. He failed, however, to recognize the aggregate form of the 

 species, although it can be concluded from his remarks (pp. 76-7) with regard to variation in specimens 

 of the aggregate form of S. runcinata-fusiformis, from the geographical location of his stations, and from 

 his figures (PI. VI, figs. 5-10) that he had a mixture of species in which such differences as I have 

 taken to be specific were regarded as mere variations within the one species — S. nmcinata-fusiformis. 

 Apstein (18946) in tropical material found two specimens of a solitary form that agreed with 

 Herdman's (1888) description of S. echinata. However, on the basis of an examination of the stolon 

 of one of the specimens, buds of the aggregate form were found and figured (fig. 14) similar to the 

 aggregate of S. fusiformis but differing in the slight lateral separation of M. IV and V. On the basis 

 of their general similarity Apstein concluded that his specimens were variants of S. fusiformis that 

 occurred only in the solitary form, and so called them S. fusiformis var. echinata (p. 15). It should 

 be noted that both Apstein (fig. 14) and Herdman (fig. 7) figure specimens of the aggregate form with 

 a lateral separation of M. IV-V, and in neither case is any significance attached to this morphological 



difference. 



Ritter (1905) described specimens similar to those of Herdman (1888) and Apstein (18946) which he 

 called S. fusiformis-runcinata form echinata. Figures 14-15 (p. 68) are the best to that date of the 

 solitary form, and show the serrations of the test in detail and the body musculature with M. IV-IX 

 parallel. Ritter's specimens were larger than those of the type S. fusiformis-runcinata and so he con- 

 sidered echinata to be a 'well-marked style or form of the species associated with age'. 



From a large collection, which included antarctic specimens, Apstein (1906) described (pp. 249-50) 

 and figured (PI. XXVI) well-serrated aggregate (fig. 4) and solitary (fig. 6) forms of S. fusiformis form 

 echinata. Unlike previous descriptions of the serrated form the solitary is shown with M. VIII-IX 

 medio-dorsally joined, while the aggregate is figured with a well-serrated test and M. IV-V not joined 



