164 QUARTERLY CHRONICLE, 



little isle of Bohol), it is probable that researches made in 

 other seas of the tropics will increase this number largely. 



E-elatively to the ciliated funnels (Entonnoirs of d'Ude- 

 kem) of the Synaptids the author affirms, as Miiller and M. 

 Baur also do, that they cannot be considered as the internal 

 terminations of the aquiferous system any more than of 

 blood-vestels. It is, then, impossible to assimilate the blood- 

 vessels of the Holothurids to the vascular excretory appa- 

 ratus of worms, and the ciliated funnels of the Synaptids 

 cannot be compared to those of Annelids. They are, with- 

 out dovibt, an apparatus destined to excite a current in the 

 liquid of the cavity of the body. 



The family of the Molpadids embraces a series of forms, 

 united, it is true, by common characters, but connected, 

 nevertheless, by certain points, to the most diverse genera of 

 other families of Holothurians. One might consider them 

 in a certain way as a collection of jDrototyniical forms. The 

 complete absence of feet apj^roximate them in appearance to 

 the Synaptids ; but the genus Echinosoma is the only one 

 which justifies entirely this approximation by the complete 

 absence of the radial canals of the skin. In the other genera 

 studied by M. Semper, the aquifei^ous canals traverse the 

 skin fully from part to part ; but instead of being prolonged 

 into feet, as in the Holothurise, they terminate in caeca, under 

 the epidermis. One part, at least, of this family appears to 

 comprise hermaphrodites species. If the family of the Mol- 

 padids comprises forms to a great extent heterogeneous, that 

 of the Dendrochirotids is, on the contrary, very uniform. 

 M. Semper is led to reduce notably the number of the genera 

 which has been increased in a large pro2:)Ortion by M. 

 Selenka. From what Ave knew till now as to this family, 

 we had the right to consider it, in opposition to that of the 

 Aspidochirolids, as belonging essentially to the boreal and to 

 the temperate region. This opinion would, however, have 

 been entirely false. Before the recent work of M. Selenka, 

 the relation of the known species in the tropical region to 

 that of the species of the temperate and boreal zones was as 

 one to twelve ; after the work of this savant, the ratio was as 

 one to five ; and now, after the study of the species of the 

 Philippines, it is become as one to one and a half. It is, 

 therefore, probable that researches made in other tropical re- 

 gions will continue to modify the ratio in the same Avay. 

 When one runs through the list of the Holothiiriai of the 

 Museum of Cambridge (Massachusets), published by M. 

 Selenka, that of the Museum of Berlin, and that of the 

 Godefroy Museum at Hamburg, one might be disposed to 



