1851.] 



319 



serrate spiculae which clothe the disc; the radial plates are more or less distinct, 

 sometimes nearly free from spiculae ; they are large and granulate, the angle which 

 is above the base of the arm nearly touches the corresponding angle of the next 

 plate, and is whitish. The oral plates are wider than long, with the oral angle 

 distinct and the lateral angles rounded; the apex is acuminate. The inner series 

 of plates bounding the oral plates is very narrow. The brachial spines are ar- 

 ranged in 7 rows, the two inferior ones being the shortest ; the others are about 

 twice as long as the diameter of the arm, and serrate from base to tip ; they are 

 transparent, with the apex frequently black. The body is dark fuscous above, 

 and pale beneath ; every fifth ventral plate on the arms is sometimes red or 

 brown. 



Some of the varieties of this species may possibly be Ophiothrix ciliaris Mul. ; 

 the young are pale colored, and very like the adults ; the plates which margin 

 the oral plates are relatively larger, being one half the size of the latter. 



PLANARI^. 

 Glossostoma. n. g. 



Body vermiform. Head continuous with the body. Eyes 10 16 in each side 

 of the head. Mouth subterminal, with a retractile tentacle on each side. Intes- 

 tinal tube ramose. Marine. 



1. G. nematoideum, pallide flavicans, pellucidum, filiforme, ocellis utrin- 

 que 10 16 minutissimis ; caecis intestinalibus brevibus obtusis. Long '1. unc. 



This animal has so little the appearance of a Planaria, that 1 long hesitated to 

 refer it to this genus; but on careful examination, I could perceive no distinct 

 character by which to separate it. The mouth is situated near the end, and on 

 the inferior surface of the body ; it is furnished on each side with a small blunt 

 retractile appendage. The ocelli are very minute, and situated on each side in 

 an oblong group, about half a line from the extremity, the abdominal cceca are 

 large and blunt. 



Elasmodes. n. g. 



Body dilated, flat. Head continuous with the body, without appendages. 

 Ocelli 5 on each side. Mouth antero-inferior, a?sophagus ventral ; intestinal tubes 

 reticulated, radiating. Marine. 



1. E. discus, latissima, planissima, pallida, pellucida, tubulis intestinalibus 

 reticulatis, tenuibus, e ventre oblongo radiantibus, ocellis utrinque 5 valde ap- 

 proximatis ab apice remotis. Long. -34, lat -25, unc. 



Very flat and thin, pellucid, only rendered darker in the middle by the slight 

 color of the intestinal tubes, which are very fine and numerous, radiating from a 

 central cavity which is five times as long as wide. Ocelli five on each side, 

 closely approximated ; groups separated by a space equal to one-third the distance 

 from them to the margin or apex. 



Typhlolepta? extensa, planissima, supra purpurea vel brunnea, mar- 

 gine pellucido, tubulis intestinalibus tenuissimis ; numerosissimis, e canali tenui 

 orientibus. Long. 1-25, lat. -32 unc. 



Less dilated than the last, but equally thin; owing to the immense number of 

 small intestinal tubes the color appears uniform, the central tube extends to within 

 two lines of each extremity. There are no visible ocelli. 



