TUNICATA OF THE PKIBILOF ISLANDS. 537 



Heed MAN, W. A. 



1882. Report on tbe Tunioata collected during the voyage of H. M. S. Challenger during the years 



1873-1876. Challenger Eeporta, Zoology, Vol. VI, 1882. 

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 Zoology. Vol. XXIII, 1891. 

 Huitfbldt-Kaas, H. 



1896. Synascidiae. Den Norske Nordhavs-Expedition, 1876-1878, XXIII, Zoologi. 

 KiiEE, John. 



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IiAHrLLE, F.. 



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 MacLeay, William S. 



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ABBREVIATIONS USED IN THE ILLUSTRATIONS. 



A Anterior, or siphonal end. 



B Base, or posterior end. 



a. 1 Atrial languet. 



a. o Atrial orifice. 



a.t Atrial tentacles. 



b. f Branchial folds. 



b. s Branchial stigmata. 



br. s Branchial sac. 



br. si Branchial siphon. 



b. t Branchial tentacles. 



d.l Dorsal lamina. 



d. t Dorsal tubercle. 



emb Embryo. 



en'c "Endooarps.'' 



ep Epicardiac tubes. 



h Heart. 



i. 1. V Internal longitudinal vessels. 



m. c. V Muscle bands of circular vessels. 



o. ce Esophageal mouth. 



o. p Optic pigment. 



09 (Esophagus. 



ov Ovary. , 



p. b Peribranohial band. 



r Rectum. 



st Stomach. 



t Testis. 



tr, tj, ts, t4 Transverse vessels of different orders. 



ts Test, or cellulose " mantle.'' 



V. d Vas deferens. 



y'k Yolk-containing mesenchyme cells. 



z Zooid. 



