332 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Anthenoides as " reticulated." Although secondary plates are pres- 

 ent on either side of the carinal series and adradial series, the 

 skeleton has not the reticulated form which one associates with 

 Anthenea. 



Anatomical notes. — Intestinal coeca composed of 5 long bifid divi- 

 sions, each terminal division Ijnng on either side of the membranous 

 interbrachial septum to which it is attached by filaments of tissue. 

 Hepatic coeca extending nearly half the length of ray; dorsal 

 stomach sharply divided from the ventral; retractors of stomach 

 attached to upper end of second ambulacral ossicle, to the proximal 

 edge of the A -shaped first ossicle, and to the dorsal integument. 

 Polian vesicle in each interradius. Gonads arranged in a series par- 

 allel to and near the interradial septum. They are not well developed 

 in the specimen dissected, but from 6 to 10 small tufts can be counted 

 in each series. In Anthenoides peircei the gonads are similarly 

 disposed. 



On the proximal part of the radial area and center of disk the 

 primary plates in regular longitudinal series are surrounded by 

 irregular small secondary^ plates which on the distal part of their 

 area are found only between the rows of primary plates. These 

 secondaries are entirely lacking on the radial areas in immature 

 specimens. Small examples may have a few in the center of disk, but 

 the difference in size between them and the primary plates is not so 

 marked. These secondary plates have 5 or 6 short lobes with trun- 

 cate facets which join truncate facets of the primary plates. The 

 number of secondary plates varies with age, an old specimen having^ 

 many, which proximally completely surround the primary plates, 

 while in smaller examples the plates are fewer and are found be- 

 tween the primaries. On the coelomic side some of the secondary 

 plates are raised into a keel, the keels radiating, 4 to 6, quite regu- 

 larly and acting as connecting ossicles between adjacent rows of pri- 

 mary plates, and sometimes between consecutive plates of the same 

 series. Other secondaries, out of position, lack the keel. Distally 

 beyond the area of secondary plates the primaries are externally 

 roundish, with truncate facets, or they may touch without a flattening 

 of the periphery. The papulae are generally distributed all over 

 the abactinal area in fully adult specimens and occur 1 to an area,, 

 as a rule, though between secondary plates occasionally 2. 



I have examined the dorsal skeleton of Anthenoides peircei and it 

 conforms to the arrangement in cristatus, although minor specific 

 differences are observable. For example, the secondary plates lack 

 a special internal keel, and, the specimen being smaller, there are 

 fewer plates. When the abactinal integument of peircei is cleared 

 with caustic potash numerous minute grains are observable, much 

 smaller than the dorsal granules of ci^tatus. 



