THE APODOUS HOLOTHTJBIANS 13 



her treated is 118, of which 26 are regarded as of doubtful standing. The 

 classic work of Ludwig ('92fc) in Bronn's Thierreich introduces an entirely 

 new basis of classification and breaks up the suborder Apoda. Ludwig shows 

 that the embryology of the Synaptidre sets them apart as a distinct group from 

 the other holothurians, and he therefore divides the class HOLOTHTJEIOIDEA into 

 two orders, the ACTINOPODA and the PARACTINOPODA, distinguished by the place 

 of origin of the circumoral tentacles. The Actinopoda include four families, of 

 which the last is the Molpadiidre, containing the footless species. The Paracti- 

 nopoda includes the single family Synaptidce. Ludwig's arrangement of 

 genera is as follows : 



Molpadiidse = Molpadia (2 species), Kupyrgus (l),!Haplodactyla (5), Caudina (4), Trochostoma 

 (12), Ankyroderma (8). 



6 genera, 32 species. 



Synaptidse - Synapta (51 species), Anapta (5), Chiridota (20), Trochodota (2), Trochodernia 

 (1), Myriotrochus (1), Acanthotrochus (1). 



7 genera, 81 sj>ecies. 

 Total, 13 genera, 113 species. 



The last important paper of the nineteenth century dealing with the classi- 

 fication of the footless holothurians is Ostergren's ('98?;) admirable revision 

 of the Synaptidae. He proposes to divide the family into three subfamilies, 

 chiefly because of differences in the calcareous deposits : Synaptinse with 

 anchors and plates, or occasionally (Anapta) only miliary granules; Chirido- 

 tinae with 6-spoked wheels, or sigmoid or bracket-shaped particles, never anchors; 

 Myriotrochinae with wheels having 8 or more spokes, never collected in papillae. 

 Under the Synaptin;r, he places Anapta and five other genera, made from the 

 old genus Synapta, as follows: Euapta, Chondrockea, Synapta, Labidoplax, 

 Protankyra. These genera are distinguished from each other mainly by the 

 shape of the tentacles and anchors and anchor-plates. Under the Chiridotinse 

 are placed two genera, Sigmodota and Chiridota, while Myriotrochus, Trocho- 

 derma, and Acanthotrochus make up the third subfamily. Altogether Oster- 

 gren recognizes 81 species of Synaptidsp, the same number listed by Ludwig six 

 years before. 



The report on the holothurians of the "Travailleur" and "Talisman," by 

 Eemy Perrier (:03), returns to the old arrangement of Brandt again, but is 

 notable for the relative rank given previously recognized groups. He con- 

 siders the apodous holothurians a natural assemblage, and ranks them as a 

 subclass, the Apodes. This subclass includes two orders, the ANACTiNOPODA 1 

 with one family, the Molpadiidae, and the PARACTINOPODA with three families, the 

 Synaptidae, Chirodotida?, and Myriotrochidap. Thus Ostergren's subfamilies are 

 here raised to fu-11 family rank. Del age and Herouard ( :04) recognize two 

 orders, ACTINOPODIDA and PAEACTINOPODIDA, under the first of which they place 



'Spelled Anactipodn on page 2(51, where first introduced ; elsewhere spelled as^ibove given. 



