W. G. Vein Name — Bermuda Ascidians. 403 



The figures showing spicules are also (with the exception of those of Cysto- 

 dytes and Echinoclinum) drawn to a uniform scale, a magnification of 450 

 diameters, and all were drawn with a camera lucida. In selecting spicules for 

 illustration, neither the largest nor the smallest, nor the extremes of variation 

 in form to be found in the colony, were chosen, but a group was selected that 

 would give a fair idea of the forms and sizes most charactei'istic of the species 

 or variety. 



In regard to the photographs of the simple ascidians, it may not be oiit of 

 place to say that all tlie Bermuda species vary endlessly in their external char- 

 acters and shape, and the writer would caution against the belief that even very 

 great differences in these characters, from the specimens illustrated, are neces- 

 sarily indicative of difference in species. With the exception of a few (men- 

 tioned in the descriptions of the figures), which were taken from living speci- 

 mens by Mr. A. Hyatt Verrill, all the photographs were made from specimens 

 preserved in formalin. 



I am indebted to Prof. A. E. Verrill for the use of the photographs from 

 which plate Ixiv and also figs. 138 and 139 were made. 



Plate XLVI. 



Figure 1. — Clavelina oblonga Herdman. Zooid containing embryos and larvae 



seen from the right side, x 12. Page 334. 

 Figure 2. — Distoma capsulatum n. sp. Zooid seen from the left side ; showing 



the arrangement of the mantle muscles, x 32. Page 341 . 

 Figures. — RhodozoyiapictaiYerviW). Zooid seen from the left side. x 8. Page- 



335. 



Plate XLVII. 



Figure 4. — Ecteinascidia furbinafa Herdman. Young individual with no repro- 

 ductive organs developed. Seen fi-om the left side, x 16. Page 338. 



Figure 5. — Rhodozona picta (Verrill). Side view of thorax to show the arrange- 

 ment of the muscle bands in the mantle. x 9. Page 335. 



Figure 6. — Ecteinascidia turbinafa Herdman. Colony of adult individuals. 

 Two-thirds the natural size. (After Herdman.) Page 338. 



Figure 7. — Clavelina oblonga Herdman. Colony of four individuals, the two on 

 the left being expanded, the others contracted as usual in preserved speci- 

 mens, x 2. Page 334. 



Figiire 8. — Perophora viridis Verrill. Individual seen from the left side, show- 

 ing outline of test and part of the branching stolen, x 32. Page 337. 



Plate XLVIII. 



Figure 9. — Distoma olivaceum, n. sp. Zooid seen from the left side. Showing 

 the arrangement of the back pigment dots on the mantle (chiefly on the 

 thorax), x 32. Musculature of mantle not shown. Page 344. 



Figure 10. — Distoma clarum, n. sp. Zooid seen from the left side, containing 

 large eggs and larvae. Showing muscle bands of mantle, x 32. Page 345. 



Figure 11. — Distoma obsciiratum, n. sp. Zooid (much contracted) seen from the 

 left side, x 32. Musculature of mantle not shown. Page 343. 



