u 



ARACHNIDA. 



provisional, and degenerates in the adult (Scorpiones, Araneae), in 

 the Opiliones it is a well-developed organ, still functional in the 

 adult, and consisting of a large coiled canal, a wide, sac-like reser- 

 voir, and an efferent duct ; the latter opening externally at the base 

 of the third ambulatory limb (Loman, No. 9).* 



V. Solifugae. f 



Of the ontogeny of the Solifugae, like that of all the Arachnida 

 already considered, so far as we are aware, very little is known. The 

 little that we do know is in connection with Galeodes araneoides, 

 some of the later ontogenetic stages of which have been described 

 by Croneberg. % 



B. 



Km. IS. — A, embryo, and II, newly-hatched young form of Galeodes araneoides (after Crone- 

 berg). a, anus ; ch, chelicerae ; peel, pedipalps ; p, limbs ; r, rostrum. 



The first embryo discovered by Croneberg was already in an 

 advanced stage, not far from hatching. In Fig. 18, A, it is seen to 

 be very like the embryo of an Araneid. As in the latter, the 

 spherical abdomen, probably well filled with yolk, forms the chief 



* [Leredinsky (App. to Lit. on Opiliones, No. V.) describes this gland in 

 Phalangium opilio as arising entirely from the mesoderm, the ectoderm only 

 sharing in the formation of the external aperture. He expresses his belief that 

 the coxal glands of Arachnids, the antennae, shell, and coxal glands of Crustacea 

 and Limulus, are all nephridia and thoroughly hemodynamic, but perhaps not 

 thoroughly homologous, some being derived from the primary and others from the 

 secondary coelom. See also, Faussek (App. to Lit. on Opiliones, No. IV). — Ed.] 



f [See Bernard, App. to Lit. on Solifugae. No. I.] 



X [BiRULA (App. to Lit. on Solifugae, No. II.) finds that the ova of Galeodes 

 develop within the cavities of the ovaries ; there are no embryonic membranes ; 

 the thoracic and abdominal segments are visible before the appendages. A 

 flexure-reversal occurs as in the Araneae. Hutton states that the Solifugae are 

 oviparous. — Ed. ] 





