SUBCLASS II 



EUCRUSTACEA— SYNCARIDA 



755 



correctly assigned to the Isopoda, however, the origin of the series must 

 have been considerably earlier. 



Vlll 



Division A. SYNCARIDA Packard.' 



Order. ANASPIDACEA Caiman. 



Carapace absent. First thoracic somite fused with the head, or defined therefrom 

 by a groove. Eyes pednncidate or 

 sessile. Thoracic legs typically toith 

 exopodites ; no oostegites. Uropods and 

 telson forming a tail-fan. 



The name Syn- 

 carida was applied 

 by Packard to a 

 group of Carboni- 

 ferous and Per- 

 mian Crustacea of 

 which the affinities 

 long remained ob- 

 scure. 



Fig. 1463. 



Anaspides tasmaniae Thomson. 



The dis- 

 covery, in the 

 fresh waters of 

 Tasmania and 

 Australia, of living forms with similar characters has thrown a new light on 



A - S 



Recent ; Tasmanm. Male, 3/,. c.gr, "Cervical 

 ^n-oove " ; ii, viii, Second and eighth thoracic somites ; 1, 6, First and sixth ab- 

 dominal somitea (after Caiman). 



Fig. 14G4 



Palaeocaris typus Meek and Worthen. Coal Measures ; Illinois. A, Restoration of body, omitting eyes, 4/^. 



B, Telson and uropods, 6/j (after Packard). 



the subject, and reinvestigation of some of the fossils has only emphasised 

 their close agreement with the Recent Anaspides (Fig. 1463) and its allies. 

 Of the fossil genera, Palaeocaris Meek and Worthen (Praeanaspides 



1 Literature : Jordan, H. , and Meyer, H. von, Crustacean der Steinkohlenforniation von 

 Saarbriicken. Palaeontogr. , 1854, vol. iv. — Brocchi, P., Note sur un Crustace, etc. Bull. Soc. 

 Geol. France, 1880, ser. 3, vol. \m.— Packard, A. S., On the Syncarida, etc. Mem. Nat. Acad. 

 Sci. Washington, 1886, vol. iii. — Thovison, G. M., On a freshwater Schizopod from Tasmania. 

 Trans. Linn. Soc. London (2) Zool., vi., 1894. — Caiman, W. T., On the Genus Anaspides, etc. 

 Trans. Roy. Soc. Edinburgh, 1896, vol. xxxviii., pt. iv. — On Pleurocaris, etc. Geol. Mag., 

 1911, dee. 5, vol. viii. — Fritsch, A., Fauna der Gaskohle, 1901, vol. iv., Heft 3, Crustacea, etc, 

 — Woodivard, H., Some Coal-measure Crustaceans, etc. Geol. Mag., 1908, dec. 5, vol. v. — 

 Sayce, 0. A., On Koonunga cursor, etc. Trans. Linn. Soc. London (2) Zool., xi., 1908. — 

 Smith, G., On the Auaspidacea, living and fossil. Quart. Journ. Microsc. Sci., 1909, vol. liii. 



