REPORT ON THE OPHIUROIDEA. 271 



Astroporpa affinis, Ltk., Addit. ad Hist., part 2, p. 154, pi. v. fig. 5, 1859. 

 West Indies ; 50 fathoms. 



Astrogomphus. 



Asfrogoinphus, Lym., Bull. Mus. Comp. Zool., vol. i., part 10, 1869. 



Disk traversed by ten narrow radiating ridges formed by the radial shields ; it, as 

 well as the arms, is covered with a minute pavement of flat granules some of which, on the 

 former, become short stout spikes. Teeth, tooth papillse, and mouth papillae all similar 

 and spiniform. The arms are simple, and their under surface is almost wholly covered by 

 side arm plates, which meet in the centre, and which bear several rough, cylindrical, ten- 

 tacle scales (or arm spines). These plates are continued upwards by a double row of 

 lumpy nodules, homologous with upper arm plates, which bear minute hooks. No under 

 arm plates. Two small genital openings in each interbrachial space at the outer corners. 



Through Astrocnida, Astrogomphus approaches the t3rpical Astrophytons, having the 

 arm belts of minute hooks, and an arrangement of side arm plates, which, with the 

 absence of under arm plates, reminds one of Astrophyton costosum. The radial shields also 

 are made up of several overlapping pieces soldered together (PL XLIV. figs. 10, 11, I). 

 Attached is a short, somewhat flattened, genital plate (fig. 10, o), to which adlieres a flat 

 and very short genital scale. The small mouth angles are very simple, and somewhat 

 recall the shape in Ophioscolex. Besides a solid transverse oval peristomial plate (fig. 

 12, %■), there is another little piece just at the upper outer corner of the mouth slit, which 

 Ludwig considers the true first under ai-m plate, and calls what usually is described as the 

 first the second. 



As might be expected in genera somewhat closely allied, Astrogomjihus has an 

 arrangement of the reproductive and digestive organs entirely comparable to that of 

 Astrocnida, except that the folds of the stomach are less complex and numerous. 



See Plate XLIV. fios. 10-12. 



o 



Species of Astrogomphus not herein described. 



Astrogomphis vallatus, Lym. (PI. XLIV. figs. 10-12). 



Astrogomphus vallatus, Lym., Bull. Mus. Comp. Zool., vol. i., part 10, p. 350, 1869 ; 111. Cat. Mu.=. 

 Comp. Zool, No. vi . pi. i. figs. 16-18; Bull. Mus. Comp. Zool., vol. v., part 9, p. 236. 



West Indies; 128 to 270 fathoms. 



Astrochele. 



Astrocliele, VU., Am. Journ. Scien., vol. xvi., 1878. 



Disk traversed by the narrow radiating ridges formed by the radial shields, and with 



the arms covered by smaU rounded scales, or grains, more or less obscured by a thick 



skin. Teeth, tooth papillae, and mouth papillse all similar and spiniform. The arms are 



