ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 311 



tive of the known Pycnogonids. The chelifori are well developed and 

 strongly chelate, the palpi are present and made up of ten joints, the 

 ovigera are present in both sexes, and are provided with denticulate 

 spines, and the trunk-segmentation is distinct. Cole puts the relation- 

 ships of the Pycnogonids in the following scheme : — 



Pycnogonomorph a 

 Pycnogonidse 



| COLOSSENDEOMORPHA 



Phoxichilidfe Pasithoidse 



Phoxichilidiidre 

 Hannonia 



Pallenidaj Ammotheidae 





Nymphonidfe 



I 

 Pentanymphon 



Eurycydidse 



Deeolopoda 



Decolopoda of Eights.* — J. C. C. Loman calls attention to the 

 description and figures of Decolopoda australis, which were given about 

 seventy years ago by James Eights. Loman says that the description 

 and figures indicate a Pycnogonid larva, probably referable to Hoek's 

 Colossendeis robusta. The larvae of Oolossendeis have cheliferse with a 

 two- jointed shaft at an age when the palps and legs have their final 

 form. Only in one respect does Decolopoda differ from all other 

 Pycnogonids — in having ten legs instead of eight, and Loman thinks 

 that Eights must have miscounted them ! " Without this supernumerary 

 pair of legs the animal is a typical Colossendeis larva ; with the ten 

 legs it is an irrational monstrosity (' ein irrationelles Monstrum ')." As 

 will be seen from the report preceding this, the " monstrosity " is a 

 reality, and there is no reason for supposing that Eights would count 

 eight as ten. 



»&* 



Myrmecophilous Acari.j — A. Berlese gives a fully illustrated account 

 of the numerous myrmecophilous Acari belonging to the group 

 Mesostigmata, including the families Uropodidas, Antennophorida3, 

 Laelaptidas, and Ganiasida?. He deals with about GO species, many of 

 which are new. 



«. Crustacea. 



Commensal Crab on a Sea-Urchin.J — E. L. Bouvier and G. Seurat 

 describe Eumedon convidor, sp. n., closely allied to E. pentagonus, 



described by A. Milne-Edwards. It was found living as an intimate 

 commensal on a long-spined sea-urchin, probably Echinothriz turcorum, 

 from the archipelago of Gambier. Commensal ism is rare in crabs of 

 the group Parthenopia?, the only other case being that of Zebrida 



* Zool. Anzeiar., xxviii. (1905) pp. 722-:l. 

 f Redia, i. (1904) pp. 299-474 (14 pis.). 

 ; Cowptes Rendus, cxl. (1905) pp. G29-31. 



