BIOLOGICAL RESULTS OF THE "AEGo" CRUISE. 211 



torn off (PI. X., figs. 5 and 6), evidently an old standing 

 injury which had involved the area of attachment and the 

 point where the blood vessels crossed from the mantle to 

 the test, as in both large tufts of hypertroplhed and freely- 

 branched vascular processes were found hanging from the 

 aperture. Fig. 7 shows the posterior end of the mantle 

 of one of these specimens with the vessels hanging from 

 it. In the other they were much more bushy. Figures 

 8, 9 and 10 show some of these abnormal vascular out- 

 growths magnified. 



Explanation of Plates VIII. 



Reference Letters. 

 a. anus; at. atrial aperture; br. branchial aperture; 

 br.f. fold in branchial sac ; cce. csecum ; d.l. dorsal lamina ; 

 d.t. dorsal tubercle ; en. endostyle ; Ji.m, h.m'. horizontal 

 membranes; i. intestine; i.l. internal longitudinal bars; 

 oe. oesophagus; r. rectum; st. stomach ; tn. tn.' tentacles; 

 tr. transverse vessels ; v. vessel of test. 



Plate YIII. 



Sketch map showing the contours of depth in fathoms,. 

 and the course of the S.Y. "Argo" in August, 1890, from 

 Greenock to Liverpool, round the West Coast of Ireland. 



1, 2, 3, &c, stations where the tow-net was used. 



A, B, C, &c, stations where dredges, &c, were used. 



Plate • IX. 

 Figs. 1- — 3. Polycarpa argoensis, n. sp. 

 Figs. 4 — 8. Molgula holtiana, n. sp. 

 Fig. 1. Pohjcarpa argoensis, from right side, nat. size. 

 2. Part of the branchial sac, X 50. 



