SI'KCIAI, CIIAHACTKIJS OF CKNITAI. 1'I.ATKS. 



in*.) 



HI 





755 755 



TEXT-FIGS. 190-196. Splitting, fusion, etc., of genital and ocular plates, in Strongylocrnt rot us and Tripririi-.! 



190. Strongylocentrotusdrobachiensis(O.F. Mutter). York Harbor, Maine. Diani. 51 rum. H. T. .1. Coll.. 77:3. X 3. 

 Genital 3 split by one horizontal suture (compare Plate 6, fig. 4). 



190a. The same. Diam. 38 mm. R. T. J. Coll., 774. X 3. Genital 3 split by one vertical suture. 

 190b. The same. Diam. 49 mm. R. T. J. Coll., 775. X 3. Genital 3 split by three sutures. 



191. The same. Calderwood Island, Maine. Diam. 46 mm. R. T. J. Coll., 879. X 3. Genital _' split. 



192. The same. Harpswell, Maine. Diam. 43 mm. R. T. J. Coll., 776. X 3. Several genitals split by secondary 

 sutures. 



193. The same. York Harbor, Maine. Diam. 46 mm. R. T. J. Coll., 711. X 4. Genitals 2,3, and oculars III. 

 V are split by secondary sutures; the splitting of oculars is a very rare variation (Plate 6, fig. 6). 



194. The same. Diam. 42 mm. R. T. J. Coll., 700. X 4. Genitals 1 and 2 much split up; ocular V split; t-xtra 

 genital pores, but there is no genital pore in the madreporite (compare text-figs. 197-199, p. 171). 



195. Thesame. Diam. 41 mm. R. T. J. Coll., 777. X 3. Genitals 3, 4 fused (compare Plate 0. fin. -: Plate 7. lv 



196. Tripneustes esculentus (Leske). Bermuda. Diam. 138 mm. R. T. J. Coll., 787. X 2. Genitals 5, 1 fused; 

 oculars V, IV, II insert (pp. 93, 124). 



