120 



AMPHIURA GEMINATA. 



LIST OF SPECIMENS. 



Catalogue Orifrinal Number 

 Number, j Number.; of Spec. 



Locality. 



When 

 Collected. 



Whence obtaiued. 



Nature of 

 Specimen. 



3Iuseum of Comparative Zoology. 



233 

 234 



36 



Norway. 



University Museum, 



Copenhagen. 

 Prof. Sai-s, 1852. 



Aleobolic. 



Amphiura geminata Lutken. 



Ophiolepis (jeminata LeConte. Proceed. Phil. Acad., Y. p. 317. 1851. 

 Amphiura (^Ophiolepis) geminata Lutkex. Addit. ad Hist. Oph., p. 122. 



Special 3IarJcs. — Arm-spines, near disk, four ; the second from below 

 a little rough and somewhat the largest. Lower arm-plates pentagonal. 



Descriptioji of a Specimen. — Diameter of disk*, 4™°"- ; from outer 

 side of mouth-shield to outer comer of opposite mouth-slit, l.T"""" ; 

 width of arm without spines, .T"""' ; length of arm, 35"""- ; distance 

 from outer side of mouth-shield to inner points of mouth-paj^illse, 

 to that between outer corners of mouth-slits, 1 : .7. Mouth-papillae, 

 three on each side, in a continuous row ; outermost one broader than 

 both the others ; two inner ones very small, rounded, bead-like. Mouth- 

 shields longer than broad, shaped like a spear-head, with the pomt 

 inward ; inner lateral sides much longer than outer ones, which are 

 short and re-enteringly curved ; length to breadth, .5 : .3 ; sometimes 

 the mouth-shield is more blunt within. Side mouth-shields proportion- 

 ately rather large, triangular, not meeting within, sides often a little 

 re-enteringly curved. Under arm-plates broader than long, pentagonal, 

 with an angle turned inward ; sides nearly straight, outer corners 

 slightly rounded ; nearly, but rarely quite, separated b}^ side arm-plates ; 

 length to breadth (tenth plate), .3 : .4 ; first plate rounded, compara- 

 tively large ; plates at tip of arm shaped much like the basal ones, but 

 more rounded, and inclining to a heart form. Side arm-plates encroach- 

 ing below pretty equally, from base to end of arm ; above, encroaching 

 less. Upper arm-plates regular, broader than long, oval, more curved 

 within than without, and tapering toward each side ; length to breadth 

 (eighth plate), .3 : .6. Disk-scales small, even, a httle larger near edge 



* This measure was taken from one of Dr. LeConte's original specimens, when dry ; the disk 

 of the Uving animal probably measured not less than 5'"'"-. 



