ASTEROIDEA 103 



C-. Abactinal paxillae small, as in C^, but superomarginal plates larger, bearing, in 

 interbrachium, 20 or more spinelets in a compact group wider than long. St. 370; 

 St. MS 74, et al. forma validus. 



C^. Superomarginal plates paxilliform, with slightly more obvious tabulum that in 

 C\ and in interbrachial area with more (18-25) spinelets. The central spinelets 

 are slender and nearly as long as the peripheral. The abactinal paxillae have 10-15 

 peripheral spinelets and 5-10 similar slender central ones (where typical validus 

 has usually 1-4 central and 5-9 peripheral spinelets). Central paxillar spinelets 

 not clavate as in meridiorialis. This variation intergrades perfectly with typical 

 validus. It resembles superficially a variant of meridionalis but can be recognized 

 by the fewer actinal spines and slender central paxillar spines. 7 specimens, St. 

 j5j forma validus. 



52. Actinal intermediate spines many to a plate, the central usually subclavate and more 

 robust than the peripheral of the group. They form a dense covering for the actinal 

 surface and are usually bent toward the margin. Marginal plates larger than in validus, 

 with numerous spines, which form a very compact group, of which the central are 

 more robust and characteristically clavate. Abactinal paxillae large, with numerous 

 central clavate spinelets surrounded by slender peripheral ones. Spines ending m 

 sharp points or awns (VII, 5-1 1). O. meridionalis. 



On account of the isolated position of Bouvet Island the three specimens from St. 

 456, 40-45 m., have been examined with great care since there was naturally some 

 expectation of finding Odontaster meridionalis. The specimens are referable to section A^ 

 of the above synopsis. One conforms to B~, while two fall under B^CS which contains 

 everything not referable to tenuis, but having somewhat longer abactinal and marginal 

 spinelets than are found in the general run of forma validus with long actinal spmes 

 (^i)_about as in Koehler VII i, where the spinelets are obviously longer than XL 7 

 and shorter than XL 6 {tenuis). 



The three specimens from St. 368 (363 m.) are of interest since one of them is the only 

 example of forma tenuis in the collection ; another is conceivably an intergrade ; while the 

 third is certainly not tenuis since it falls under A^ of the synopsis, yet has longer, 

 slenderer rays than the typical form of validus. There is great variation in the size of the 

 madreporite in all phases of validus. The figure of tenids given by Koehler (1920, pi. 40, 

 fig. 3) shows a large plate. In the Bouvet Island specimen it is about one-half this size. 

 A few specimens of undoubted forma validus have the madreporite as large as in this 

 figure of tenuis. 



Our largest specimens are from St. 370, South Sandwich Island. Of these the largest 

 has R 70 mm., r 25 mm., br 25-28 mm., breadth of madreporite 11 mm. The rays are 

 rather slender and obviously long, the rays being longer in proportion to disk than in 

 Koehler's figures of tenids, which this specimen clearly is not. The smallest from St. 

 370 has R 49 mm., r 22 mm., br 26 mm., breadth of madreporite, 3-5 mm. This 

 specimen is a typical forma validus with swollen disk, small, well-spaced paxillae, the 

 superomarginals of interbrachial region having about 12 spinelets. The mouth angles 

 are worthy of close attention, for each has 3 "teeth", the normal recurved median, 

 and a shorter one on either side, such as characterize Koehler's " Epidontaster" and 



5-2 



