THE APODOUS HOKOTHUKIANS 15 



In discussing the classification of the Synaptidae, the question naturally 

 arises whether the subfamilies suggested by Ostergren ('985) are worthy of 

 recognition. Subfamilies may be quite as natural groups as families, but if they 

 are simply artificial assemblages they needlessly complicate the classification, 

 unless the number of genera is unusually large, which is certainly not the case 

 with the Synaptidae. That Ostergren 's subfamily Synaptinae is a natural group 

 seems very probable, the genera contained in it being evidently related to each 

 other. There is more room for question whether the Chiridotinae and Myrio- 

 trochinaa can be properly separated from each other, but the calcareous particles 

 are certainly strikingly different in the two groups, and it is at least probable 

 that no violence is done in separating them. But Perrier's ( :03) proposition 

 to make full families of these subdivisions of the Synaptidae cannot be ap- 

 proved without exaggerating their differences. 



In attempting to define genera or species in the Synaptinae, we are met with 

 the difficulty that many are known from a single specimen or at most a few, and 

 nothing is recorded of their life histories. Especially is this true of the various 

 East Indian species, and since, in those species whose life history has been 

 studied, it is known that the number of tentacles gradually increases as the 

 animal approaches maturity, it is very probable that some of the 10- and 13- 

 tentacled species will prove to be the young of other 12- or 15-tentacled forms. 

 Moreover, many species have been described from fragments, the anterior end 

 of the body being missing, and consequently the species are based wholly on 

 the calcareous particles, which is of course unfortunate ; for it ought to be 

 clearly understood that the calcareous particles in the skin of Synaptids (as in 

 all holothurians) are more or less variable, and while each species usually has 

 its own distinct sort, yet there is a very wide range of diversity, even in one in- 

 dividual, and exact conformity to a given type must not be expected or looked 

 for. The six genera proposed by Ostergren appear in the main to be natural 

 groups, and will doubtless be quite generally accepted. But unfortunately in 

 selecting his names, Ostergren overlooked or ignored some of his predecessors. 

 The name Synapta was proposed by Eschscholtz ('29) for a species which he 

 called mammillosa, and he also states that Holothuria maculata Chamisso and 

 Eysenhardt is congeneric. There can be little question that these two species 

 are the s.ame, in spite of .the extraordinary difference in the colored figures 

 given (see page 79), and it is further reasonably sure that they are no other 

 than the species well known as beselii Jager. The name Synapta must there- 

 fore be retained for this species, which Ostergren puts in his genus Chondro- 

 cloea. Owing to its unique anchor-plates, and some other peculiarities, it is 

 better to regard it as sui generis, and let the other members of "Chondrocloea" 

 stand apart. They cannot, however, be called by Ostergren 's name, for 

 among them is "vivipara" (=hydriformis Lesueur), which was made the type 



