PLATE 4. 



Salenia pattersoni A. Agassiz. 



Figs. 1-5. Off Havana, Cuba. 300 fathoms. Diam. 112 mm. R. T. J. Coll., 669. All drawn from a single specimen. 



Fig. 1. Apical disc seen from the exterior. X 6. Ocular I is insert, all others exsert; ocular and genital pores invisible; 

 lew madreporic pores in genital '_'; suranal plate is opposite genital 3. Pages 112, 172. 



Fig. 2. Apical disc seen from the interior. X 6. Pores are visible in all ocular and genital plates; only one madreporic 

 opening in genital 2, though there are several pores on the exterior of the same plate, fig. 1. Page 172. 



Fig. '■>. Segment of lantern, showing a keeled tooth, foramen magnum deep and open above, narrow epiphyses, brace and 

 compass. X 12. (Compare text-rig. 212. p. 184.) Page 186. 



Fig. 4. The lantern with muscles and perignathic girdle seen from above. X 12. In area IV all parts of the lantern 

 are in place; in V the compass is removed: in I the brace is removed and also the epiphysis of one side, showing 

 therefore in this area on one side an epiphysis, and on the other side the top of the pyramid with its pits. Protractor, 

 /</., and radial compass muscles, r, are inserted on low apophyses; retractors are inserted on styloid auricles. (Com- 

 pare fig. .5.) Pages 186, 195. 



fig. 5. To show thr perignathic girdle and attachment of lantern muscles to the same. X 12. Protractor and radial 

 compass muscles are inserted on the low apophyses, ap., retractors on the styloid auricles, au. Page 195. 



Salenocidaris varispina A. Agassiz. 



Fig. 6. Lesser Antilles, 687 fathoms Diam. 7 mm. R. T. .1. Coll., litis. X 12. Ocular I insert, others all exsert. 

 Ocular and genital pores visible; suranal plate opposite genital 3. Pages 112, 174. 



Peltastes wrighti Desor. 



Fig. 7. Greensand, Cretaceous. Farringdon, England. Diam. 12.5 mm. K. 4". ,J. Coll., 674. x 4. All oculars exsert; 

 the suranal plate is opposite ocular III. Pages 111, 174. 



Stomopneustes variolaris (Lamarck). 



Fig 8 Ceylon. R. T. .1. (.'oil . 862 :i Segment of the lantern; tooth keeled, foramen magnum deep, epiphyses 



narrow, qo1 meeting in suture; dorsally the half-pyramids extend over the foramen and produce spurs which support 

 the tooth. Page 186. 



Fig. '.i. Same specimen. ■ :'> Dorsal portion of a half-pyramid to show spur of the same that supports the tooth; epi- 

 physis removed Page 186. 



Fig. ID. Another specimen, same locality, li. T. .1 Coll., Mis. X 4. Dorsal view of a pyramid, on one side with epi- 

 physis in place, on the other side the epiphysis is removed to show pits in the pyramid, which dorsally by its spurs 

 gives support to the tooth. Page 186. 



Arbacia punctulata (Lamarck). 



Fig. 11. Woods Hole. Massachusetts. Diam. :;:'> mm. P.. 4". .1. Coll., 685. X 3. Interambulacrum 4 has only one 

 column of plates dorsally. genital 4 is absent, oculars IV and V are in contact and cover entirely areas IV, 4, and V. 

 (Compare Bothriocidaris, Plate 1, fig. 2; Tripneustes, Plated, fig, 4.) Pages 45, 88. 



Fig. 12. Florida. R. T. J. Coll., 889. X 3. Genital 4 is wanting, therefore oculars IV, V arc in contact and cover 

 ambulacra IV. V, and interambulacrum 4 completely. There are two columns of plates in interambulacrum 4 as 

 usual. (Compare lig. 11 and text-fig. 185, p. 167.) Page 46. 



