THE APODOUS HOLOTHURIANS 89 



Remarks. — This species is apparently the central one of the genus from 

 which the others appear to have been derived, and it is, as one would therefoi'e 

 suppose, the most variable of all. Besides the characters already given, it 

 may be added that the number of digits varies (probably with age) from 3-10 

 on each side, but is usually 5-7, and the terminal one is the longest, with the 

 adjoining ones nearly as long; the sense-cups vary from 2-14 on each tentacle, 

 but there are usually about 8 ; there is no distinct stomach nor is the intestine 

 conspicuously looped; the ciliated funnels are numerous and of two distinct 

 sizes; reproductive organs long and branched. (For an excellent detailed ac- 

 count of the specific characters, see Ostergren :05ff; for notes on habits, and 

 physiology, see Clark, '99i.) Whether the common white Synapta of the New 

 England coast is really distinct from the European species is regarded by 

 Ostergren (:05) as an open question, but it is exceedingly difficult to find any 

 differences of importance; those mentioned by Ostergren are certainly trivial. 

 A careful comparison between individuals from Norway (for which beautiful 

 specimens my thanks are due Dr. Ostergren), Naples, California, and Woods 

 Hole has failed to bring out a single constant difference, although I am not 

 sure that the Pacific Coast form may not prove distinct, when living specimens 

 are studied. The anchors and plates are noticeably smaller in these specimens 

 than in those from Norway, but the Woods Hole and Naples specimens are in- 

 termediate and no real line of division can be drawn. Too much emphasis 

 must not be placed on either dimensions or proportions of the calcareous 

 particles, not only because they vary so much, even in specimens from a single 

 locality, but because in measuring such minute objects the "personal equa- 

 tion" is a factor not to be ignored. Ostergren suggests that the American 

 form may be regarded as a distinct variety or subspecies, if not a fully ac- 

 credited species ; but I fail to see what would be gained by such a course, and, 

 moreover, I can find no other ground than locality by which to distinguish it. 

 For the present, therefore, I must believe that inhcerens is (or has been) a cir- 

 cumpolar species and extends its range southward on both coasts of America 

 as well as in Europe. 



Leptosynapta dolabeifera. 



Synapta dohirifera Stimpson, 1856, p. 386. 



Length. — 50-90 mm., with a diameter of about 4 mm. 



Color. — Dirty yellowish. 



Distribution. — Port Jackson, New South Wales. 



Eemarks. — Besides the characters given above in the key, there are several 

 others which aid in the recognition of this species. Stimpson 's description is 

 accurate, but not very complete, and as nothing further has ever been published, 

 the following notes will be of value : Of the six specimens examined, four had 



