504 PROFESSOR E, RAY LANKESTER, 
Limutus an Aracunip. By E. Ray Lanxester, M.A., 
F.R.S., Jodrell Professor of Zoology in University 
College, London. (With Plates XXVIII and XXIX). 
A. IntRopuction AND BiIBui0o- V. Hypothesis as to their 
GRAPHY. mode of origin. 
VI. Entosternite. 
B. Comparison oF LIMULUS AND ; 
ScoRPIO § c. Alimentary canal. 
i § d. Vascular system. 
§ a. Nervous system. § e. Generative glands. 
§ 4. Skeleton. C. THe EvrypTerina as A CON- 
I. Tergites. NECTING LINK. 
II. Appendages. D. Review or opinions or MoDERN 
ILI. Sternites. AUTHORITIES AS TO THE 
IV. The common charac- AFFINITIES OF LIMULUS. 
ters of the lamelligerous | E. Conctusions: LimuLus aAwnpD 
appendages of Scorpio THE ANCESTRY OF TRa- 
aud Limulus. CHEATE ARTHROPODA, 
A. INTRODUCTION AND BIBLIOGRAPHY. 
Tue prevailing opinion among zoologists at the present 
day, with regard to the affinities of the King Crab, is that 
it must be regarded as one of the Crustacea. Even when 
this view is not fully accepted the King Crab is placed in a 
special position of isolation and its relationship with Crus- 
tacea strongly insisted upon, whilst more remote affinity 
with the Arachnida is grudgingly admitted. 
My friend Edouard Van Beneden, of Liége, is the only 
zoologist who has definitely taken a divergent line, and has 
frankly endorsed the instinctive perception of Straus Durk- 
heim in declaring that Limulus is no Crustacean, but simply 
and unreservedly an Arachnid. Ed. Van Beneden bases his 
opinion upon embryological data. I have elsewhere ex- 
pressed my full cuncurrence in that opinion, but the grounds 
upon which my conclusion rests are not solely embryological 
—they have reference to the structure of the adult Limulus 
and Scorpion. In the following pages I hope to show that 
Limulus is best understood as an aquatic scorpion, and the 
Scorpion and its allies as terrestrial modifications of the 
King Crab. 
My views on this subject were formed some eight years 
ago, and I have to acknowledge the kinduess of Mr. Car- 
rington, F.L.S., of the Royal Westminster Aquarium, by 
which I have been enabled to dissect and make histological 
study of perfectly fresh specimens of Limulus sent to me in 
the living state. 
