404 MR. H. M. BEENARD ON THE 



altogether an imaginary drawing. While closely watching an Epeira in a bottle, 

 protruding and retracting its spinnerets, I noticed that in their most protruded condition 

 they had the shape represented in this figure. The spinning-glands might thus well be 

 the setiparous sacs of the original setae at the tips of the branches of the parapodia. 

 This origin of the limbs will explain the two series of glands on each side, above referred 

 to (p. 383), one opening at the ends of limbs or laterally, and the other near the median 

 line. In this way we might have spinning-glands placed distally on the limbs, tracheae 

 derived from the specialized aciciilar glands of vanishing parapodia laterally along the 

 ventral surface, and spinning- and cement-glands near the median line. 



Turning lastly to the Hexapods and Myriapods, we find that the leg can be deduced 

 from the venti'al parapodium, while the dorsal parapodium disappeared, leaving, however, 

 the acicvilar gland as a tracheal invagination, and the setiparous areas either scattered as 

 hairs or persisting in areas (pupa of Orgia antiqua) or partly developing into stink- 

 glands (foramina repugnatoria of the Myriapods). PI. XXXIV. fig. 18, C, is not so 

 unlike the section of a Lepidopterovis larva in which the stump-like legs are armed at 

 their distal ends with numerous hooked setae. Here, again, as in the case of the 

 Arachnids, we should have the acicular glands only persisting where a parapodium has 

 vanished. 



These three possible origins of the trunk appendages of the chief divisions of the 

 Arthropods are as distinct as are the specializations of the anterior segments with their 

 appendages for the purposes of feeding above suggested. 



I am thus disposed to look upon the Crustacea, the Arachnida, the Hexapoda, and the 

 Myriapoda as distinct specializations of a Chaetopod Annelidan type, and in no way 

 deducible the one from the other. 



REFERENCES. 



1. Balfouk. — Notes on the Development of the Araneina. Quart. Journ. Micro. Sci. xx. 1880. 



2. Beck, Miss. — Description of the Muscular and Eadoskeletal Systems of Scorpio. Trans. Zool. Soc. 



xi. p. 311. 1885. 



3. Benham. — Description of the Muscular and Eudoskeletal Systems of Limulus. Trans. Zool. Soc. 



xi. p. 339. 1885. 



4. Bernard. — The Apodidse. ' Nature ' Series. London, 1893. 



5. Bernard. — The Apodemes of Apus, and the Endophragmal System of Astacus. Ann. & Mag. 



Nat. Hist., July 1892. 



6. Bernard. — Some Observations on the Relations of the Acaridae to the Arachnida. Journ, Linn. 



Soc, Zool. xxiv. p. 279. 1892. 



7. Bernard. — An Endeavour to show that the Tracheae of the Arthropoda arose from Setiparous Sacs. 



Zool. Jahi-b. Abth. Anat. Bd. 5. 1892. 



8. Bernard. — Additional Notes on the same subject. Ann. & Mag. Nat. Hist. xiii. 1894. 



9. Bernard. — Tne Head of Galeodes, and the Procephalic Lobes of Arachnidan Embryos. Zool. 



Anzeiger, no. 426. 1893. 



10. Bernard. — Notes on the Chcrnetida\ Journ. Linn. Soc, Zool. xxiv. 1893. 



11. Bernard. — Notes on some of the Digestive Processes in the Arachnids. Journ. R. Micro. Sci. 1893. 



12. Bernard. — The Coxal Glands of Scorpio. Ann. & Mag. Nat. Hist. xii. p. 55. 1893. 



13. Bernard. — The Endosternite of Sco/yio, &c. Ann. & Mag. Nat. Hist. xiii. 1894. 



