562 RECORD OF CURRENT RESEARCHES RELATING TO 



dence of the breeze ; 17. A bright warm day in October is coinmonly 

 chosen for the ascent ; and 18. Judging from the presence of a number 

 of dry moults upon many posts, apparently of the same species of spider 

 observed in flight, the animals had recently cast their skins. Of the 

 above points, Nos. 3, 7, 9, 10, 11 in part, 12, 14 in part, 15 in part, 

 and 18 are those which were determined by the last observation. 



The object of this interesting habit seems to be the distribution of 

 species. 



New and other Pycnogonida.*— Dr. Bohm has a technical paper 

 on the Pycnogonida of the Eoyal Zoological Museum at Berlin, and 

 on the forms found by the corvette ' Gazelle.' 



The following new forms are described : — NympTion phasmatodes 

 from the Cape of Good Hope ; N. horridum from Kerguelen ; Pallene 

 lappa from the Mozambique, where it was found on Ophiocoma erinaceus; 

 PhoxichiUdium digitatum from Singapore; Pycnogonum c/jeZa/wm (habitat 

 unknown) ; and the new genus Gorniger (Achelidce), which is remarkable 

 for having the antennary jaws comj^osed of one segment, whereas in 

 Achelia there are two, and in Zetes three segments. A beautiful series 

 can now be made out ; in the Nymphonidce these organs have three 

 joints and are scissor-shaped, in the Achelidce they are simple, but may 

 consist of one, two, or three joints, and in the Pycnogonidce they are 

 absent. The species of this genus is named Hilgendorfi, and was 

 obtained from Enosima, Japan. It is also pointed out that the 

 accessory ova-bearing appendages of Nymphon have eleven, and not, as 

 Semper says, nine joints, and that the species obtained from Kerguelen 

 is not the same as the N. gracilipes Heller of the Northern seas, and 

 it is therefore called Helleri. The characters of the genus Pallene are 

 reconsidered, and the new species are figured, with some already 

 known, in two plates. The paper is of value to those who are 

 interested in the study of these curious but difficult Pseudarachnoid 

 forms. 



Form of the Muscular Contraction in the Crayfish.f— M. Eichet 

 is rightly of opinion that it is of interest to compare the phenomena 

 observed in this crustacean with what has been seen in the frog ; he 

 shows that all the caudal muscles have a short period of contraction ; 

 that of the pincers is much longer than that of any muscle in the 

 frog, save only the cardiac ; it lasts nearly ten times as long as that 

 of the tail-muscle ; the " time lost " when the muscle is excited 

 through the agency of the ganglionic cliain is very great, amounting as 

 it does to 2-5 hundredths of a second ; the tail-muscles soon lose 

 their contractility after repeated shocks, and it is pointed out that this 

 is quite in accordance with the habits of the animal, which never 

 swims for a long period at one time ; the muscles of the pincer 

 behave very differently, and this too is what we should expect from 

 the holding power of the animal ; finally, this organ, under appropriate 

 conditions, retains its power of contractility four days after sej^aration 

 from the body. 



* ' MB. K. Akad. wiss. Berlin,' 1879, p. 170. 

 t ' Comptes Rendus,' Ixxxviii. (1879) p. 868. 



