350 BULLETIN OF THE 



nute, usually simple, sickle-shaped hook ; these correspond to arm-spines, hut 

 gradually disappear towards the base of the arm, where, however, the double 

 rows of grains are still to be recognized. Tentacle spines short, small, tooth- 

 like ; on most of the pores two, but some within the disk have three. Gen- 

 ital slits large 10 mm. long, and extending from the under to the upper 

 skin of the disk. 



Variations. — Another specimen of about the same size had some small 

 spines in the interbrachial spaces of the upper disk, and from nine to fourteen 

 spines on each radial rib. On the under surface of the disk the granulation 

 of the skin near the mouth was prolonged into the under surface of the 

 arms, between the tentacle pores. 



Florida, in 120 and 125 fathoms. 



Astrogomphus Lyman, pen. now* 



Disk with ten low, very narrow radial ribs, running nearly to its centre, 

 and beset with numerous spines. Arms simple. Skin of arms and disk 

 covered by a mosaic of small flat grains ; the joints of the former distin- 

 guished by ridges, each of which consists of belts of granules, some of them 

 bearing minute hooks. Arm-spines like thorny stumps, and arranged in 

 clumps just above the tentacle pores. Teeth: tooth-papilla? and mouth- 

 papillse all similar and spiniform. Two genital slits in each interbrachial 

 spaee. 



Astrogomphus belongs with the simple-armed Astrophytons. In the dis- 

 tinctness of its disk, and the character of the surface of its arms, it some- 

 what resembles Trichaster, while its dentition is rather like that of 

 Astroporpa. 



Astrogomphus vallatus Lyman. 



Special Marks. — The whole upper disk beset with short, very stout 

 spikes, arranged rudely in concentric rows; under surface paved with 

 smooth, Hat grains, except a fence of stout papilla 1 , which runs between the 

 lower sides of the arms, where they join the disk. 



Description of n Specimen. — Diameter of disk 17 mm. Length of arm 

 100 mm. Width of arm next the disk li.a mm. ; height of arm 3 mm. 

 Mouth-papilla 1 and tooth-papilla similar to each other, short, sharp, stout; 

 mouth-papillae about ten on each side, arranged in two irregular rows, one 

 above the other; toot h-papilhe about twelve, arranged in irregular pairs 

 along the point of the jaw; the longest are, .8 mm. ; and both mouth and 

 tooth papillae are spiniform, sharp, rounded, and perfectly smooth. Arms 

 high and rounded above, flattened below; they are divided by depressions 



* aarrjp, star; yofi0os, spike. 



