464 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



addition to the two forms, new to science, already diagnosed, Mr. 

 Sladen describes a new Crinoid, to wliich he gives the name of 

 Antedon prolixa. As a general conclusion of their studies, the authors 

 find that the fauna with which they have had to do is essentially 

 circumpolar ; they give careful descriptions of what variations they 

 have seen— variations which, with so great an area, may, of course, 

 be considerable. 



Echinoidea of the 'Gazelle' Expedition.* — This expedition 

 brought back only forty-one species, of which, according to Professor 

 Studer, seven were new to science. With regard to known species, 

 the localities in the region of New Britain offer some interesting 

 intermediate stations for those known to dwell in both the Pacific and 

 the Indian Oceans. The ' Challenger ' brought home one species of 

 the genus Catopygus of the Secondary epoch, and Dr. Studer now 

 describes a second. A fuller account is now given of the genus 

 Schleinitzia (S. crenularis), which Studer named in 1876. The author 

 directs attention to the crenulation of the tubercles in this and allied 

 forms, and comes to the (to be expected) conclusion that the character 

 is not one of generic value ; he finds it to obtain when the spines are 

 largely developed, so that the crenulation is comparable to the deve- 

 lopment of muscular ridges. Astropyga elasiica, described in 1876, is 

 now partially figured. An Echinometra was observed working on the 

 clialk of a coral reef by its jaws. A new species, now for the first 

 time described, is Amblypneustes grossidaria, though the author thinks 

 that it may be a young Ibrra (only a single specimen was found). He 

 is not able to associate it with any of the species of which accounts 

 have been given by Agassiz or Bell. The other new species are 

 Catopygus Loveni, Spatungus (Leucophorus) interruptus, Hemiaster fiori- 

 gerus, and Schizaster capensis. 



Locomotor System of Echinodermata.f— Messrs. G. J. Eomanes 

 and J. C. Ewart have especially devoted themselves to the ambulacral 

 and nervous systems ; they find that the former is shut ofi" from the 

 so-called blood-vascular system except at the madreporic plate. The 

 latter communicates much more freely with the internal medium, a 

 pressure of two feet during a number of hours being requisite to force 

 the fluid injected into the stone canal through the madreporic plate. 

 In Echinus lateral branches arise from the five radial nerve-trunks, 

 and i^ass through the pores of the pore-plates. Each of these 

 branches courses down a pedicel, and they give off" other branches, 

 which unite to form an intimate nerve-plexus which invests the whole 

 external surface of the test, and passes to all the spines or pedicel- 

 lariae. Physiological, though no histological, evidence was also obtained 

 as to the presence of a nerve-plexus on the inner surface of the test. 



Experiments revealed " a high degree of co-ordination " in the 

 natural movements of the Echinodcrms ; all, when inverted on a flat 

 surface, are able to right themselves. " The common starfish does 

 this by twisting the ends of two or more rays round, so as to bring the 



* MB. K. Preuss. Akad. (1S80) pp. 861-84 (2 pis.). 

 5 t Pioc. Roy. Soc. See ' Xatuie,' xxiii. (1881) pp. 545-7. 



