734 IGERNA B. J. SOLLAS. 



appendages belonging to tlie anterior region of the body, 

 besides one foremost pair wliicli serves as an organ of 

 attachment, and is inserted into the tissues of the host. 



The systematic position and diagnosis of the genus may 

 be stated as follows : — Synascida Didemnida Didemnina, 

 (Y. Delage). Colony thin; ascidiozoids Avith four rows of 

 branchial slits and twenty-four tentacles ; vas deferens 

 spirally coiled round the testis ; ftecal pellets included in the 

 test, in which organ the renal vesicles are likewise contained. 



In conclusion, it gives me much pleasure to take this 

 op|)ortunity of expressing my thanks to Mr. Graham Kerr 

 for kind help and advice. 



Literature consulted. 



Hekdman. — ' Voyage of H.M.S. Clialleiiger,' Tunicata ii. 

 Yves Delage. — 'Zoulogie concrete,' viii. 

 Daiilgkun, W. — 'Arcliiv fiir uat. Mikr.,' Iviii, 1901. 

 GiAiU). — ' Arcli. d. Z. exper.,' i, 1872. 



EXPLANATION OF PLATES 34 & 35, 



Illustrating Igerna B. J. Sollas's paper "On Hypurgou 

 Skeati, a New Genus and Species of Compound 

 Ascidiaus." 



as. Calcaicoiis spicule. ciLs. Atrial siplion. bd. c. IMood-corpusclc. bl.c. 

 Vehicular cell of Icsl. hl.s. Blood-sinus. d.L Doisallanguel. d.l. Dorsal 

 tubercle, end. Entloslyle. f. i'\isiforni cell. g. Nerve ganglion. //. llearl. 

 int. Intestine. /. Larva, n. tc. Notocliord. en. CEsopliagus. vv. Ova. ji. 

 Ficcal pellet, p.c. rericardiuni. reel. Rectum, r. Renal organ. r.(/l. 

 Glandular cells of rcuid organ. r.c. Renal coiicictiou. si. Stomach. L 

 Testis, v.app. Vasr. appendage, v.d. Vas deferens. 



