SEP 9 1898 



[ 305 ] 



IV. The Comparative Ilorphologij of the Galeodidae. By H. M. Bernard, 3LA. Cantab.^ 

 F.L.S., F.Z.S. {From the Huxley Research Laboratory, Royal College of Science.) 



(Plates XXVII.-XXXIV.) 



Bead 7th February, 1895. 



Contents, _ 



Page 



Introduction 305 



Historical , 307 



I. The External Form and Segmentation 308 



II. The Internal Apodematous Skeletal System 319 



III. The Limbs 321 



IV. The Cuticle and its Derivatives, and the Hypodermis 330 



V. The Muscular System 335 



VI. The Nervous System 341 



VII. The Sense Organs 345 



VIII. The Alimentary Canal 355 



IX. The Heart and Circulation 365 



X. The Kespiratory System 371 



XI. Excretory Organs 377 



XII. Reproductive Organs 384 



XIII. Summary, an attempt to elucidate the Phylogeny of the Arachnida 387 



XIV. Bibliography 404 



XV. Explanation of the Plat«s 407 



Introduction. 



A COMPARATIVE study of the Arachnidan family, the Galeodidge *, has long been a 

 desideratum. The chief sources of our knowledge of this family date back to times 

 before the all-absorbing questions of ancestry had made morphology the fascinating 

 study it now is. The Artbrojiods, for many reasons, have long been recognized as 

 presenting a rich field for investigation in this direction, and most modern works deaUng 

 with the mor^ihology of any Arthropod form contain discussions as to the probable 

 affinity of the family described with other members of the group, and its bearing on 

 the ancestry of the Arthropods in general. Of such discussions, none have been carried 

 on so vigorously as that on the affinities of the Arachnida. 



This controversy, for such it is, arose out of an attempt to connect the Arachnids 

 with the ancient aquatic Merostomata, one form of which, Limulns, is still extant. This 

 suggested relationship, though widely accepted, has been also strenuously opposed. Some 

 opponents confine themselves to a purely negative attitude, others prefer to see distant 

 affinities with the lusecta. The Galeodidae are largely responsible for this suggested 



* This name was given by Ohvier, 1791, and, according to Dufour, referred to the resemblance of the cephalic 

 lobes to a helmet {galea). Others, however, would deduce it from the Greek yaXeri, a weasel-like animal, in refer- 

 ence, no doubt, to the light colour and rapid movements of the commoner species. The name Soljiuga was given later 

 by Herbst, 1797. 



SECOND SERIES. — ZOOLOGY, VOL. VI. 41 



