:276 SUMMARY OF CURRENT RESEARCHES RELATING TO 



appendages of the second mesosoraatic somite, possibly also by the ven- 

 tral plates. The second mesosomatic appendages have inner and outer 

 branches, like the corresponding appendages of Limuhs, and the outer 

 branch, though in some respects resembling the pecten of a scorpion, 

 also resembles the outer branch of a mesosomatic limb in Limulus. 



Genera of Hydrachnids.* — F. Koenike discusses the species of the 

 genera Arrenurus and Eylais, and criticises Piersig's treatment of these 

 species in his work on German Hydrachnids. 



Adaptation of Instinct in a Trap-door Spider.f — E. I. Pocock puts 

 on record a case (from Western Australia) of a spider making the lid of 

 its hole out of a sixpence. There was only silk thread on the top of the 

 coin, but underneath mud and silk thread were coated on and shaped 

 convex as usual. 



Mites and Tardigrades.} — Prof. F. Richters, in studying the moss- 

 fauna around Frankfurt, came across the rare Oribatid Cepheus ocellatus 

 Michael, and he gives a description of it, accompanied by some beautiful 

 figures. He acknowledges with some enthusiasm his indebtedness to 

 Michael's work. A second section is devoted to the eggs of Oribatids. 

 Thirdly, the author describes OpMocamptus muscicola sp. n., a moss-in- 

 habiting Copepod. The fourth section of the communication describes 

 a new Tardigrade, Macrobiotus ornatus. 



e. Crustacea. 



Antennal Glands and Shell-Glands in Crustacea.§ — Prof. F. Vejdov- 

 sky finds that in the antennal glands of the Gammaridae the secreting 

 tubule, which he regards as the nephridium proper, opens by a narrowed 

 orifice into the end-sac, or ccelom-sac as he regards it. Into this orifice 

 large cells project, forming a funnel which communicates on the one side 

 with the nephridium, and on the other with the ccelom-sac, nephridium 

 and funnel being the homologues of the similar structures in an Annelid. 

 In the shell-glands of Isopods he finds similar large cells at the junction 

 of canaliculus and end-sac (ccelom-sac), constituting a similar funnel 

 apparatus. So striking is the resemblance in both cases to the Annelid 

 nephridium, that the author states that, from the standpoint of compara- 

 tive anatomy, there is no difference between the excretory organs of 

 Annulata and Crustacea. The funnel in Crustacea certainly differs in the 

 small number of its component cells and the absence of cilia ; but these 

 the author regards as modifications due to functional change in the 

 method of discharge of the waste-products. 



Habits of Cambarus immunis Hagen.|| — J. A. Harris has some notes 

 on the burrows constructed by this American crayfish during the period 

 when the shallow pools in which it lives dry up, and also at the 

 approach of winter. He finds that the burrowing habit has no apparent 

 connection with the hatching of the eggs. The burrows are of con- 

 siderable size ; one was followed up for 4 feet without reaching the end, 



* Zool. Anzeig., xxiv. (1901) pp. 90-6 (1 fig.). t Nature, lxiii. (1901) p. 466. 



X Ber. Senckenberg. Ges., 1900, pp. 21-44 (4 pis.). 



§ Zeitschr. wise. Zool., lxvi. (1901) pp. 378-97 (2 pis. and 1 fig.). 



|| Amer. Nat., xxxv. (1901) pp. 187-91. 



