372 



PROF. F. J. BELL ON HOLOTHTJRIA NIGRA. [May 20, 



EXPLANATION OF THE PLATES. 



Fig. 1. 

 2. 

 3. 

 4. 

 5. 



Fig. 1. 

 2. 

 3. 

 4. 

 5. 

 6. 



Cioniscus gracilis, p. 341 



striatus, p, 342. 



Odostomia suboblonga, p. 345. 



tenuis, p. 347. 



— nitens, p. 349. 



Plate XXVI. 



Fig. 6. Odostomia pralonga, p. 350. 



7. crassa, p. 350. 



8- unifasciata, p. 351. 



9. sigmo'idea, p. 354. 



10. ftexuosa. p. 355. 



Plate XXVII. 



Odostomia sinuosa, p. 358. 



acuticostata, p. 359. 



fulgidula, p. 359. 



at.tenuata, p. 360. 



compressa, p. 360. 



paucistriata, p. 361. 



Fig. 7. Odostomia semicostata, p. 361. 



8. Pi/ramidella nitidula, p. 363. 



9. Mathildaquadricarimata (apex), 



p. 364. 

 10. Gegania pinguis, p. 365. 



2. 

 3. 

 4. 

 5. 



. 366. 



Fig. 1. Eulitna jeffreysiana, p 



2. ■ ■ glabra, p. 367. 



stalioi, p. 368. 



- solida, p. 368. 



- fusco-apicata, p. 369. 



Plate XXVIII. 



Fig. 6. Eulima piriformis, p. 369. 



7. ■ ahbreviata, p. 370. 



8. subumbilicata, p. 370. 



9. minuta, p. 370. 



10. obtusa, p. 370. 



3. Studies in the Holothuroidea. — IV. On the Structural 

 Characters of the Cotton- Spinner (Holot/mria nigra), 

 and especially of its Cuvierian Organs. By F. Jeffrey 

 Bell, M.A., F.Z.S V Professor of Comparative Anatomy 



in King's College. 



[Keceived May 15, 1884.] 



Scattered through zoological literature there are here and there 

 references to a Holothurian, of which Selenka appears to have had 

 no knowledge, and which Semper places among the " giinzlich 

 zweifelhaften Arten," but which, unless patriotism is a fault in a 

 man of science, ought to be of interest to British naturalists in so 

 far and inasmuch as it is not only the only known British repre- 

 sentative of the restricted genus Ilolothuria, but it is, so far as we 

 know at present, the only member of the family of Aspidochirotae, 

 or Holothurians with shield-shaped tentacles and no retractors for 

 the pharynx, that is found in our seas. Discovered shortly after the 

 publication of Forbes's ' British Starfishes ' — which, like every other 

 work from that accomplished pen, had a remarkable influence on 

 his contemporaries — it was first mentioned and described to a scien- 

 tific audience by Mr. C. "W. Peach in 1844, who appears (see 

 Report, 1844, p. 65) to have satisfied the members of the British 

 Association that, in introducing to them the " nigger or cotton- 

 spinner," he was speaking of a Holothurian new to the British 

 fauna. A communication on this animal was read by Mr. Peach to 

 the Royal Polytechnic Institution of Cornwall, and is to be found, 

 with an illustrative plate, on pp. 1/1-1 74 of the 'Annals and Magazine 



