210 SYSTEMATIC ARRANGEMENT 



14. D. tomentosa, t. 231. f. 8. 



15. D. coccinea, t. 271. f. 1 ; Forbes fy Hartley, B.M. t. V.V. f. 2. 



16. D. nigricans, t. 229. f. 1. 



17. D. ?, t. 230. f. 1. 



18. D. albolimbata, t. 213. f. 2. 



19. D. tenera, t. 214. f. 5. 



20. D. luteo-rosea, t. 229. f. 4. 



21. D. punctata, t. 218. f. 2. 



22. D. ?, t. 233. f. 1. 



23. D. Candida, t. 269. f. 4. Gill on middle of back. 



Central tooth of Doris obvelata minute, erect, base expanded, 

 apex rounded, cutting edge bent down, crested and denticulated ; 

 lateral teeth on both sides about 20, each of them a bent hook ser- 

 rulated on the lower margin, scape shorter ; teeth in the middle of 

 the series the largest (fig. 115). 



Fig. 115. — Teeth of Doris obvelata. 



" The dorsal tentacles of D. tuberculata conical ; oral tentacles 

 tubercular ; cloak with hard spiculose tubercles. Lingual spines 

 simple, uniform; no central spine." — Loven. 



" The dorsal tentacles of D. Zetlandica conical ; oral tentacles 

 tubercular ; cloak with soft tubercles. Lingual spines long, linear, 

 obtuse, denticulated ; no central spine. 



" In B. Johnstonii the dorsal tentacles clavate ; oral tentacles 

 linear. Lingual spines of two forms ; no central spine. 



" The dorsal tentacles of D. repanda linear ; oral tentacles angu- 

 lar, flattened. Lingual spines denticulated ; a small central spine. 

 Mouth with a spinous collar." — Alder. 



** Gills set separately round the vent, and each retractile into its 

 proper cavity. 



9. Hexabranchus. 



Mantle very large, flat, waved on the edge. Dorsal tentacles lami- 

 nated, kneed, retractile within marginated cavities ; oral tentacles 

 large, ovate, waved on the edge. Gill tree-like, in a ring. Teeth 



1. II. pretextus, t. 237. 



2. II. sanguineus, t. 68. f. 4. 



3. II. laciniatus, t. 65. f. 3, t. 230. f. 2. 



4. II. marginalia, t. 221. f. 2, t. 221. f. 2. 



5. II. Sandwichensis, t. 235. 



6. II. Adamsii, t. 219. f. I, 



