250 BULLETIN OF THE 



7. Ophiothrix maculata Ljn\ Josephine Bank, 120 fathom?, off Portugal. 



8. Ophiothrix Lutkeni Wvv. Tiioms. Southwest of Ireland, 374 fathoms. 

 Of these species, I consider the first four and the last as well marked ; the re- 

 maining three, perhaps, need to be illustrated by more specimens and localities. 



It may be proper to add, that the foregoing critique is simply intended as a 

 guide to the naturalist who has sufficient specimens of these species for study. 



Astrophyton cacaoticum sp. now 



Plate VI., Figs. 1-3. 

 Special Marls. — Disk and arms essentially smooth with only a few micro- 

 scopic grains. Radial ribs high, narrow, and well-marked. Arms unusually 

 slender and forking close to the disk; with hook-bearing ridges feebly raised 

 above the general surface. Five madroporic bodies. 



Description of a Specimen (dried). — Diameter of disk 30 mm. Arm forked 

 close to disk. Width of arm C mm. ; of each fork 3 mm. Each then con- 

 tinues as a slender, slowly tapering main trunk, throwing out side branches 

 on alternate sides, and these branches in like manner throw out side twigs. 

 Distance from first. fork to second 1 7 mm. 



" " second 



" " third 



" " fourth 



" " fifth 



" " sixth 



" " seventh 



" " eighth 



" " ninth 



" " tenth 



" " eleventh 



" « twelfth 



" " thirteenth 



Total, 286 " 



Along the upper surface of the arm are scattered microscopic granules, 

 which are still fewer and more minute than those of the disk ; on an alco- 

 holic specimen these granules would doubtless be invisible. Beginning near 

 the mouth there are two pointed tentacle-spines, 5 mm. long, on each pore, 

 beyond the first fork usually three; and these continue nearly to the tips of 

 the arm, where they are replaced by the hook-bearing ridges, here composed 

 of a double ring of large prominent grains encircling the arm, and with but 

 a short space from one ridge to the next. Each grain bears a minute simple 



] k. Except at the tip of arm, the hook-bearing ridges are small and 



low, and separated from each other by a considerable smooth space. The 



