Ech inoderma . 217 



III. OPHIUROIDEA. 



A large nuinber of specimens of two species were collected, both 

 of wliich are representatives of new generic types, allied to Opliinra 

 {Ophioijhj'pha of Mr. Lyman), l)ut distinguished by several striking 

 charactei'S. These new genera are perhaps the most valualjle 

 additions to our zoological knowledge made by the 'Southern Gross' 

 Expedition. There are also two specimens of an Ophiactis, which 

 recalls at once 0. asperula, Phil., known from the southern parts of 

 South America, but which is distinguished by the want of delicate 

 spines at the edge of the disc ; the condition of preservation of the 

 collection does not justify one in coming to any conclusion as to the 

 exact position of this form. There are moreover three specimens of 

 a creature which appears to be allied to, if not a member of, the 

 genus 02)hioviusium, but this is a group which requires revision 

 before any addition is made to it ; it will be sufficient to put on 

 record that an Ophiomusiam-Wke Ophiurid has penetrated into 

 Antarctic waters. 



7. OpIIIOZONA INEllMIS. 



An Ophiozona with two small tentacle-scales at base of arm and 

 none further out. Three minute peg-like arm-spines. Eadial 

 shields inconspicuous and separated. Side arm-plates large and 

 meeting below. 



Diameter of disc, 10:9:12 mm. 



Length of arm (ca.), 25 : 25 : 28. 



This is a type not uncommon among Ophiurids, where there are 

 many forms so distinct as to be called " species," but exhibiting no 

 morphological characters of any apparent interest or significance. 



Cape Adare, 26 fathoms, 28-5° Fahr. 



OPHIOSTEIRA. 



This new genus is remarkable for the possession of a large 

 keel-like plate on the disc, at the base of each arm, which completely 

 overshadows the radial shields. The arms are compressed laterally, 

 so that they are almost triangular in cross-section ; the upper arm- 

 plates are separated from one another by a slight groove, and stand 

 up high so as to give both a serrated and a keeled appearance to the 



