Invertebrate Gallery of the Indian Museum. 8i 



In Pycnogonum, as in the Spiders, the stomach is pro- 

 longed into the legs, almost to their end. 



Most of the Pycnogonida are small, and are to be found 

 crawling about among the sea-weed between tide-marks, 

 but some of the deep-sea species are of gigantic size— the 

 specimen of Colossendeis ^igas from the depths of the 

 Andaman Sea, exhibited in Case 58, having a span of over 

 eighteen inches. 



The stomach of this specimen is distended with mud, 

 so that its tubular prolongations into the legs is beautifully 

 displayed. This specimen is a male, and also shows well 

 the position and nature of the egg-carrying legs. 



4. ARTHROPODA ARACHNIDA. 



[QEtstern SEall-raBeg 58, 60-62]. 



The Arachnida include the worm-like Pentastomtda, 

 the Mites and Ticks, the Spiders, the Spider-like Phalan- 

 giida, the Scorpion-spiders, the Book-scorpions, and the 

 Spider-like Solifugse. 



The Class thus contains a great variety of forms which, 

 in addition to the fact that they are all built on the 

 Arthropod plan of a succession of segments or somites, 

 have the following characters in common : — (i) that they 

 breathe air, commonly by tracheal sacks or "lungs," but 

 sometimes by true tracheal tubes, {2) that the head 

 and thorax are always fused together to form a single 

 mass, (3) that they possess two pairs of organs that can 

 be used as jaws, and four pairs of legs — six pairs of limbs 

 in all, and (4) that the abdomen has no limbs. 



The disarticulated specimen of the scorpion in Case 61 

 shows the number and arrangement of the appendages of 

 the Arachnid body. 



i.— ARACHNIDA ARANEIDA. (True Spiders). 

 [SEc0t£rn ®aU-ca0C 60]. 

 We may very well commence the study of the Arack- 

 nida with the large specimens and preparations of the 



