34 University of California Publications in Zoology. [ VoL - 6 



appear to be protectively colored. The abundance and ease of 

 collection of the littoral species leads me to believe that hybridi- 

 zation experiments might be worth trying and that the eggs might 

 also be favorable for many other problems in experimental embry- 

 ology. It would be of interest in this connection to know what 

 species ai-e viviparous. 



In giving the diameter of the disc the largest specimen at 

 hand was always chosen. Most of the species have been described 

 and figured elsewhere, but the following descriptions and figures 

 have the advantage to the student at San Diego in all being made 

 from the region where his material will be procured. No dissec- 

 tions are described; for example, only the exposed part of the 

 radial shield is described. 



Types or representatives of all are in the University of Cali- 

 fornia museum, except Oplrioenida hispida, which is in the United 

 States National Museum. The figures were drawn by the author, 

 excepting 24 and 25, which were drawn by Mr. G. T. Kline. 



Class OPHIUROIDEA Norm. 1865. 



Order 1. ZYGOPHIURAE Bell 1892. 

 Ophiuroidea with well-developed parts in the skeleton of the 

 arm segments. The arms are not branched and cannot be rolled 

 up toward the mouth. 



Suborder A. BRACHYOPHIURAE E. Perr, 1891. 

 Arm spines short, parallel to the arm axis. 



Family 1. Ophiodermatidae Ljg. 1867. 



With numerous mouth papillae, no tooth papillae, 2-4 genital 

 openings. 



Genus Ophioderma. 

 Ophiura Lm. 1801 (partim). 



Disc granulated. Teeth, and numerous, equal, close-set mouth 

 papillae. No tooth papillae. Spines smooth, flat, shorter than 

 arm joints, numerous (7-13). Two tentacle scales; only the 

 upper one covers the base of the last arm spine. A notch in the 



